Subcutaneous electrode for transthoracic conduction with low profile installation appendage

ABSTRACT

Electrical cardiac therapy devices including electrode lead assemblies having appendages coupled to an electrode. The appendage may take the form of a riser and a head having various characteristics. A further embodiment may include a cover and/or other features coupling the electrode to the riser. A lead may be provided for electrical coupling to the electrode. The lead may couple to the electrode exclusive of the riser and head. An implantable housing containing electrical circuitry for using the electrode to stimulate cardiac activity is also illustrated.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationentitled “SUBCUTANEOUS ELECTRODE FOR TRANSTHORACIC CONDUCTION WITH LOWPROFILE TNSTALLATION APPENDAGE AND METHOD OF DOING SAME,” having Ser.No. 09/940,340, filed Aug. 27, 2001, now U.S. Pat. No. 6,937,907; whichis a continuation-in-part of U.S. patent application entitled “UNITARYSUBCUTANEOUS ONLY IMPLANTABLE CARDIOVERTER-DEFIBRILLATOR AND OPTIONALPACER,” having Ser. No. 09/663,606, filed Sep. 18, 2000, now U.S. Pat.No. 6,647,292, and U.S. patent application entitled “SUBCUTANEOUS ONLYIMPLANTABLE CARDIOVERTER-DEFIBRILLATOR AND OPTIONAL PACER,” having Ser.No. 09/663,607, filed Sep. 18, 2000, now U.S. Pat. No. 6,721,597, ofwhich both applications are assigned to the assignee of the presentapplication, and the disclosures of both applications are herebyincorporated by reference.

In addition, the present application is related to U.S. application Ser.No. 09/940,283, filed Aug. 27, 2001 and entitled “DUCKBILL-SHAPEDIMPLANTABLE CARDIOVERTER-DEFIIBRILLATOR CANISTER AND METHOD OF USE,” nowU.S. Pat. No. 7,065,407; U.S. application Ser. No. 09/940,371, filedAug. 27, 2001 and entitled “CERAMICS AND/OR OTHER MATERIAL INSULATEDSHELL FOR ACTIVE AND NON-ACTIVE S-ICD CAN,” now U.S. Pat. No. 7,039,465;U.S. application Ser. No. 09/940,468, filed Aug. 27, 2001 and entitled“SUBCUTANEOUS ELECTRODE FOR TRANSTHORACIC CONDUCTION WITH IMPROVEDINSTALLATION CHARACTERISTICS,” abandoned; U.S. application Ser. No.09/941,814, filed Aug. 27, 2001 and entitled “SUBCUTANEOUS ELECTRODEWITH IMPROVED CONTACT SHAPE FOR TRANSTHORACIC CONDUCTION,” abandoned;U.S. application Ser. No. 09/940,287, filed Aug. 27, 2001 and entitled“SUBCUTANEOUS ELECTRODE FOR TRANSTHORACIC CONDUCTION WITH INSERTIONTOOL,” abandoned; U.S. application Ser. No. 09/940,377, filed Aug. 27,2001 and entitled “METHOD OF INSERTION AND IMPLANTATION FOR IMPLANTABLECARDIOVERTER-DEFIBRILLATOR CANISTERS,” now U.S. Pat. No. 6,866,044; U.S.application Ser. No. 09/940,599, filed Aug. 27, 2001 and entitled“CANISTER DESIGNS FOR IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS,” now U.S.Pat. No. 6,950,705; U.S. application Ser. No. 09/940,373, filed Aug. 27,2001 and entitled “RADIAN CURVE SHAPED IMPLANTABLECARDIOVERTER-DEFIBRILLATOR CANISTER,” now U.S. Pat. No. 6,788,974; U.S.application Ser. No. 09/940,273, filed Aug. 27, 2001 and entitled“CARDIOVERTER-DEFIBRILLATOR HAVING A FOCUSED SHOCKING AREA ANDORIENTATION THEREOF,” now U.S. Pat. No. 7,069,080; U.S. application Ser.No. 09/940,378, filed Aug. 27, 2001 and entitled “BIPHASIC WAVEFORM FORANTI-BRADYCARDIA PACING FOR A SUBCUTANEOUS IMPLANTABLECARDIOVERTER-DEFIBRILLATOR,” now U.S. Pat. No. 7,146,212; U.S.application Ser. No. 09/940,266, filed Aug. 27, 2001 and entitled“BIPHASIC WAVEFORM FOR ANTI-TACHYCARDIA PACING FOR A SUBCUTANEOUSIMPLANTABLE CARDIOVERTER-DEFIBRILLATOR,” now U.S. Pat. No. 6,856,835;and U.S. application Ser. No. 09/940,471, filed Aug. 27, 2001 andentitled “POWER SUPPLY FOR AN IMPLANTABLE SUBCUTANEOUS IMPLANTABLECARDIOVERTER-DEFIBRILLATOR,” now U.S. Pat. No. 7,076,296; thedisclosures of which applications are hereby incorporated by reference.

FIELD

The present invention relates to an apparatus and method for performingelectrical stimulation of the heart via an implantable system.

BACKGROUND

Defibrillation/cardioversion is a technique employed to counterarrhythmic heart conditions including some tachycardias in the atriaand/or ventricles. Typically, electrodes are employed to stimulate theheart with electrical impulses or shocks, of a magnitude substantiallygreater than pulses used in cardiac pacing.

Defibrillation/cardioversion systems include body implantable electrodesand are referred to as implantable cardioverter/defibrillators (ICDs).Such electrodes can be in the form of patches applied directly toepicardial tissue, or at the distal end regions of intravascularcatheters, inserted into a selected cardiac chamber. U.S. Pat. Nos.4,603,705; 4,693,253; 4,944,300; and 5,105,810, the disclosures of whichare all incorporated herein by reference, disclose intravascular ortransvenous electrodes, employed either alone or in combination with anepicardial patch electrode. Compliant epicardial defibrillatorelectrodes are disclosed in U.S. Pat. Nos. 4,567,900 and 5,618,287, thedisclosures of which are incorporated herein by reference. A sensingepicardial electrode configuration is disclosed in U.S. Pat. No.5,476,503, the disclosure of which is incorporated herein by reference.

In addition to epicardial and transvenous electrodes, subcutaneouselectrode systems have also been developed. For example, U.S. Pat. Nos.5,342,407 and 5,603,732, the disclosures of which are incorporatedherein by reference, teach the use of a pulse monitor/generatorsurgically implanted into the abdomen and subcutaneous electrodesimplanted in the thorax. This system is far more complicated to use thancurrent ICD systems using transvenous lead systems together with anactive can electrode and therefore it has no practical use. It has infact never been used because of the surgical difficulty of applying sucha device (3 incisions), the impractical abdominal location of thegenerator and the electrically poor sensing and defibrillation aspectsof such a system.

Recent efforts to improve the efficiency of ICDs have led manufacturersto produce ICDs which are small enough to be implanted in the pectoralregion. In addition, advances in circuit design have enabled the housingof the ICD to form a subcutaneous electrode. Some examples of ICDs inwhich the housing of the ICD serves as an optional additional electrodeare described in U.S. Pat. Nos. 5,133,353; 5,261,400; 5,620,477; and5,658,321 the disclosures of which are incorporated herein by reference.

ICDs are now an established therapy for the management of lifethreatening cardiac rhythm disorders, primarily ventricular fibrillation(V-Fib). ICDs are very effective at treating V-Fib, but are therapiesthat still require significant surgery.

As ICD therapy becomes more prophylactic in nature and used inprogressively less ill individuals, especially children at risk ofcardiac arrest, the requirement of ICD therapy to use intravenouscatheters and transvenous leads is an impediment to very long termmanagement as most individuals will begin to develop complicationsrelated to lead system malfunction sometime in the 5-10 year time frame,often earlier. In addition, chronic transvenous lead systems, theirreimplantation and removals, can damage major cardiovascular venoussystems and the tricuspid valve, as well as result in life threateningperforations of the great vessels and heart. Consequently, use oftransvenous lead systems, despite their many advantages, are not withouttheir chronic patient management limitations in those with lifeexpectancies of >5 years. The problem of lead complications is evengreater in children where body growth can substantially altertransvenous lead function and lead to additional cardiovascular problemsand revisions. Moreover, transvenous ICD systems also increase cost andrequire specialized interventional rooms and equipment as well asspecial skill for insertion. These systems are typically implanted bycardiac electrophysiologists who have had a great deal of extratraining.

In addition to the background related to ICD therapy, the presentinvention requires a brief understanding of automatic externaldefibrillator (AED) therapy. AEDs employ the use of cutaneous patchelectrodes to effect defibrillation under the direction of a bystanderuser who treats the patient suffering from V-Fib. AEDs can be aseffective as an ICD if applied to the victim promptly within 2 to 3minutes.

AED therapy has great appeal as a tool for diminishing the risk of deathin public venues such as in air flight. However, an AED must be used byanother individual, not the person suffering from the potential fatalrhythm. It is more of a public health tool than a patient-specific toollike an ICD. Because >75% of cardiac arrests occur in the home, and overhalf occur in the bedroom, patients at risk of cardiac arrest are oftenalone or asleep and can not be helped in time with an AED. Moreover, itssuccess depends to a reasonable degree on an acceptable level of skilland calm by the bystander user.

What is needed therefore, especially for children and for prophylacticlong term use, is a combination of the two forms of therapy which wouldprovide prompt and near-certain defibrillation, like an ICD, but withoutthe long-term adverse sequelae of a transvenous lead system whilesimultaneously using most of the simpler and lower cost technology of anAED. What is also needed is a cardioverter/defibrillator that is ofsimple design and can be comfortably implanted in a patient for manyyears.

SUMMARY

The present invention, in an illustrative embodiment, includes animplantable lead electrode assembly comprising an electrode, a risercoupled to the electrode, and a head coupled to the riser. Theimplantable lead electrode assembly may have various shapecharacteristics in several embodiments. For example, in one embodimentthe riser is substantially planar. In another embodiment, the head issubstantially planar.

In a further embodiment, the riser comprises a proximal end, a distalend, a top, and a bottom, where the proximal end is closer to the distalend at the top of the riser than at the bottom of the riser. Theinvention may further include a lead coupled to the electrode. In someembodiments, the lead may be coupled to the electrode without couplingthrough the riser or head, and/or the lead may be coupled to theelectrode closer to the distal end of the electrode than the proximalend of the electrode.

In yet another embodiment, the lead assembly may further include abacking layer and a foundation having a front side and a back side. Thebacking layer can be disposed between the front side of the foundationand the electrode, and the riser may then be secured to the back side ofthe foundation. In such an embodiment, the backing layer and/orfoundation may electrically insulate a side of the electrode.

The invention may also include, in an illustrative embodiment, a coverassembly including a skirt partially covering a front side of theelectrode, and a back portion, wherein the back portion and the risergenerally electrically isolate a back side of the electrode. Inadditional embodiments, an implantable housing containing electricalcircuitry for providing electrical therapy to a patient's heart may beprovided along with these various illustrative lead assemblyembodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the invention, reference is now made tothe drawings where like numerals represent similar objects throughoutthe figures where:

FIG. 1 is a schematic view of a Subcutaneous ICD (S-ICD) of the presentinvention;

FIG. 2 is a schematic view of an alternate embodiment of a subcutaneouselectrode of the present invention;

FIG. 3 is a schematic view of an alternate embodiment of a subcutaneouselectrode of the present invention;

FIG. 4 is a schematic view of the S-ICD and lead of FIG. 1subcutaneously implanted in the thorax of a patient;

FIG. 5 is a schematic view of the S-ICD and lead of FIG. 2subcutaneously implanted in an alternate location within the thorax of apatient;

FIG. 6 is a schematic view of the S-ICD and lead of FIG. 3subcutaneously implanted in the thorax of a patient;

FIG. 7 is a schematic view of the method of making a subcutaneous pathfrom the preferred incision and housing implantation point to atermination point for locating a subcutaneous electrode of the presentinvention;

FIG. 8 is a schematic view of an introducer set for performing themethod of lead insertion of any of the described embodiments;

FIG. 9 is a schematic view of an alternative S-ICD of the presentinvention illustrating a lead subcutaneously and serpiginously implantedin the thorax of a patient for use particularly in children;

FIG. 10 is a schematic view of an alternate embodiment of an S-ICD ofthe present invention;

FIG. 11 is a schematic view of the S-ICD of FIG. 10 subcutaneouslyimplanted in the thorax of a patient;

FIG. 12 is a schematic view of yet a further embodiment where thecanister of the S-ICD of the present invention is shaped to beparticularly useful in placing subcutaneously adjacent and parallel to arib of a patient;

FIG. 13 is a schematic of a different embodiment where the canister ofthe S-ICD of the present invention is shaped to be particularly usefulin placing subcutaneously adjacent and parallel to a rib of a patient;

FIG. 14 is a schematic view of a Unitary Subcutaneous ICD (US-ICD) ofthe present invention;

FIG. 15 is a schematic view of the US-ICD subcutaneously implanted inthe thorax of a patient;

FIG. 16 is a schematic view of the method of making a subcutaneous pathfrom the preferred incision for implanting the US-ICD;

FIG. 17 is a schematic view of an introducer for performing the methodof US-ICD implantation;

FIG. 18 is an exploded schematic view of an alternate embodiment of thepresent invention with a plug-in portion that contains operationalcircuitry and means for generating cardioversion/defibrillation shockwaves;

FIG. 19( a) is a side plan view of an embodiment of a lead electrodeassembly with a top-mounted fin;

FIG. 19( b) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted fin;

FIG. 19( c) is a side plan view of a section of the lead in anembodiment of the lead electrode assembly;

FIG. 19( d) is a cross-sectional view of a filar in the lead in anembodiment of the lead electrode assembly;

FIG. 19( e) is a cross-sectional view of the lead fastener of anembodiment of a lead electrode assembly;

FIG. 19( f) is an exploded view of the lead fastener of an embodiment ofa lead electrode assembly;

FIG. 20( a) is a cross-sectional front plan view of an embodiment of alead electrode assembly with a top-mounted fin;

FIG. 20( b) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted fin;

FIG. 21 is a perspective view of an embodiment of a lead electrodeassembly with a top-mounted fin;

FIG. 22( a) is a cross-sectional side plan view of an embodiment of alead electrode assembly with a top-mounted fin and a molded cover;

FIG. 22( b) is a cross-sectional side plan view of an embodiment of alead electrode assembly with a top-mounted fin that is slope-shaped anda molded cover;

FIG. 22( c) is cross-sectional front plan view of an embodiment of alead electrode assembly with a top-mounted fin and a molded cover;

FIG. 22( d) is an exploded top plan view of the lead fastener in anembodiment of a lead electrode assembly with a top-mounted fin and amolded cover;

FIG. 22( e) is a bottom plan view of an embodiment of a lead electrodeassembly with a top-mounted fin and a molded cover;

FIG. 22( f) is a side plan view of an embodiment of a lead electrodeassembly with a top-mounted fin and a molded cover;

FIG. 22( g) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted fin and a molded cover;

FIG. 23( a) is a side plan view of an embodiment of a lead electrodeassembly with an elongated top-mounted fin and a molded cover;

FIG. 23( b) is a top plan view of an embodiment of a lead electrodeassembly with an elongated top-mounted fin and a molded cover;

FIG. 23( c) is a bottom plan view of an embodiment of a lead electrodeassembly with an elongated top-mounted fin and a molded cover;

FIG. 24 is a side plan view of a lead electrode assembly demonstratingthe curvature of the electrode;

FIG. 25( a) is a top plan view of the backing layer and electrode of anembodiment of a lead electrode assembly with a side-mounted fin;

FIG. 25( b) is a side plan view of the backing layer and electrode of anembodiment of a lead electrode assembly with a side-mounted fin;

FIG. 25( c) is a bottom plan view of an embodiment of a lead electrodeassembly with a side-mounted fin;

FIG. 25( d) is a bottom plan view of an embodiment of a lead electrodeassembly with a side-mounted fin with a slope-shape;

FIG. 26( a) is a side plan view of a lead electrode assembly with atop-mounted loop;

FIG. 26( b) is a cross-sectional rear plan view of a lead electrodeassembly with a top-mounted loop;

FIG. 26( c) is a top plan view of a lead electrode assembly with atop-mounted loop;

FIG. 27( a) is a top plan view of a backing layer for use in anembodiment of a lead electrode assembly with a top-mounted fin formed aspart of the backing layer;

FIG. 27( b) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted fin formed as part of the backing layer;

FIG. 27( c) is a side plan view of an embodiment of a lead electrodeassembly with a top-mounted fin formed as part of the backing layer;

FIG. 27( d) is a front plan view of an embodiment of a lead electrodeassembly with a top-mounted fin formed as part of a backing layer;

FIG. 27( e) is a side plan view of an embodiment of a lead electrodeassembly with a top-mounted fin formed as part of a two-piece backinglayer;

FIG. 27( f) is a front plan view of an embodiment of a lead electrodeassembly with a top-mounted fin formed as part of a two-piece backinglayer;

FIG. 28( a) is a front plan view of the embodiment of the lead electrodeassembly of FIGS. 27( e) and (f) in an upright position;

FIG. 28( b) is a front plan view of the embodiment of the lead electrodeassembly of FIGS. 27( e) and (f) illustrating the ability of the fin tofold;

FIG. 29( a) is a front plan view of an embodiment of a lead electrodeassembly with a top-mounted tube formed as part of a backing layer;

FIG. 29( b) is a side plan view of an embodiment of a lead electrodeassembly with a top-mounted tube formed as part of a backing layer;

FIG. 29( c) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted tube formed as part of a backing layer;

FIG. 30( a) is a front plan view of an embodiment of a lead electrodeassembly with a top-mounted fin connected with flexible joining materialin an upright position;

FIG. 30( b) is a front plan view of an embodiment of a lead electrodeassembly with a top-mounted fin connected with flexible joining materialin a folded position;

FIG. 30( c) is a top plan view of an embodiment of a lead electrodeassembly with a top-mounted fin connected with flexible joining materialin an upright position;

FIG. 31 is a perspective view of an embodiment of a lead electrodeassembly in which the appendage is a cylindrical tube;

FIG. 32 is a perspective view of an embodiment of a lead electrodeassembly in which the appendage is a tube with a substantiallytriangular cross section;

FIGS. 33( a)-(d) are top plan views of embodiments of lead electrodeassemblies illustrating shapes of the electrode and the lines of thelead;

FIGS. 33( e)-(h) are bottom plan views of embodiments of lead electrodeassemblies illustrating shapes of the electrode;

FIG. 34 is a perspective view of a custom hemostat for lead electrodeassembly implantation;

FIG. 35( a) is a perspective view of a patient's ribcage showing theorientation of the components in an implanted S-ICD system;

FIG. 35( b) is a cross-sectional side plan view of a patient's rib cage,skin, fat and the lead of the lead electrode assembly;

FIG. 36 is a front plan view illustrating the incision point for thesurgery to implant the lead electrode assembly;

FIG. 37( a) is a cross-sectional bottom plan view of a patient alongline 32(a) of FIG. 31 illustrating the creation of a subcutaneous pathfor implantation of the lead electrode assembly of an S-ICD system;

FIG. 37( b) is a perspective view of a lead electrode assembly capturedby a custom hemostat;

FIG. 37( c) is a cross-sectional bottom plan view of a patient alongline 32(a) of FIG. 31 illustrating the implantation of a lead electrodeassembly via the subcutaneous path;

FIG. 37( d) is a top view of a lead electrode assembly captured by acustom hemostat;

FIG. 38( a) is a perspective view of a rail of an embodiment of the leadelectrode assembly;

FIG. 38( b) is a cross-sectional front plan view of an embodiment of thelead electrode assembly where the appendage is a rail;

FIG. 38( c) is a top plan view of an embodiment of the lead electrodeassembly where the appendage is a rail;

FIG. 39 is a top view of an embodiment of the lead electrode assemblywhere the appendage is a rail;

FIG. 40( a) is a perspective view of a lead electrode assemblymanipulation tool with a rail fork;

FIG. 40( b) is a top plan view of a lead electrode assembly manipulationtool with a rail fork;

FIG. 40( c) is a side plan view of a lead electrode assemblymanipulation tool with a rail fork;

FIG. 40( d) is a top plan view of a lead electrode assembly having arail captured by a lead electrode assembly manipulation tool with a railfork;

FIG. 41( a) is a cross-sectional side plan view of a lead electrodeassembly with a pocket;

FIG. 41( b) is a top plan view of a lead electrode assembly with apocket;

FIG. 41( c) is a cross-sectional side plan view of a lead electrodeassembly with a pocket and a fin;

FIG. 42( a) is a bottom plan view of a lead electrode assembly with apocket;

FIG. 42( b) is a top plan view of a lead electrode assembly with apocket;

FIG. 43( a) is a top plan view of a lead electrode assembly manipulationtool with a paddle;

FIG. 43( b) is a side plan view of a lead electrode assemblymanipulation tool with a paddle;

FIG. 43( c) is a top plan view of a lead electrode assembly with apocket captured by a lead electrode assembly manipulation tool with apaddle;

FIG. 44( a) is a cross-sectional rear plan view of a lead electrodeassembly with a first channel guide and a second channel guide;

FIG. 44( b) is a top plan view of a lead electrode assembly with a firstchannel guide and a second channel guide;

FIG. 45( a) is a top plan view of a lead electrode assembly manipulationtool with a channel guide fork;

FIG. 45( b) is a top plan view of a lead electrode assembly with a firstchannel guide and a second channel guide captured by a lead electrodeassembly manipulation tool with a channel guide fork;

FIG. 46( a) is a perspective view of a subcutaneous implantablecardioverter-defibrillator kit; and

FIG. 46( b) is a perspective view of a hemostat illustrating the lengthmeasurement.

DETAILED DESCRIPTION

For the purposes of the following description, the terms “proximal” and“distal” take the following meanings. For a device temporarily insertedand manipulated by a physician, the proximal end of the device is thedevice that the physician grasps, or is the end of the device whichextends out of the patient. For permanently implanted devices such asthe ICD devices discussed herein, the proximal end of a lead assemblyrefers to the end of the lead assembly which connects to a canistercontaining the operational circuitry of the ICD. The distal end, in eachcase, refers to the end of an elongate medical device opposite theproximal end.

Turning now to FIG. 1, the S-ICD of the present invention isillustrated. The S-ICD includes an electrically active canister 11 and asubcutaneous electrode lead assembly 13 attached to the canister. Thecanister 11 has an electrically active surface 15 that is electricallyinsulated from an electrode connector block 17 and a canister housing 16via insulating area 14. The canister 11 can be similar to numerouselectrically active canisters 11 commercially available in that thecanister 11 will contain a power supply and operational circuitry.Alternatively, the canister 11 can be thin and elongated to conform tothe intercostal space. The circuitry will be able to monitor cardiacrhythms for irregularities (such as fibrillation or tachycardia), and ifdetected, will initiate a process for deliveringcardioversion/defibrillation energy through the active surface 15 of thehousing and to the subcutaneous electrode lead assembly 13. Examples ofsuch circuitry are described in U.S. Pat. Nos. 4,693,253 and 5,105,810,the entire disclosures of which are herein incorporated by reference.The canister circuitry can provide cardioversion/defibrillation energyin different types of waveforms. In the preferred embodiment, a biphasicwaveform is used of approximately 10-20 ms total duration and with theinitial phase containing approximately ⅔ of the energy, however, anysuitable waveform can be utilized (e.g., monophasic, biphasic, and/ormultiphasic).

In addition to providing cardioversion/defibrillation energy, thecircuitry can also provide transthoracic cardiac pacing energy. Theoperational circuitry would then be able to monitor the heart forbradycardia and/or tachycardia rhythms. Once a bradycardia ortachycardia rhythm is detected, the circuitry can then deliverappropriate pacing energy at appropriate intervals through the activesurface and the subcutaneous electrode. Pacing stimuli are preferablybiphasic (though any other suitable waveform may be used as well) andsimilar in pulse amplitude to that used for conventional transthoracicpacing.

This same circuitry can, alternatively, also be used to deliver lowamplitude shocks on the T-wave for induction of ventricular fibrillationfor testing S-ICD performance in treating V-Fib as is described in U.S.Pat. No. 5,129,392, the entire disclosure of which is herebyincorporated by reference. Also the circuitry can be provided with amode for rapid induction of ventricular fibrillation or ventriculartachycardia using rapid ventricular pacing. Another optional way forinducing ventricular fibrillation would be to provide a continuous lowvoltage, i.e., about three volts, across the heart during the entirecardiac cycle.

Another optional aspect of the present invention is that the operationalcircuitry may be adapted to detect the presence of atrial fibrillationas described in Olson, W. et al. “Onset And Stability For VentricularTachyarrhythmia Detection in an Implantable Cardioverter andDefibrillator,” Computers in Cardiology (1986) pp. 167-170. Detectioncan be provided via R-R cycle length instability detection algorithms.Once atrial fibrillation has been detected, the operational circuitrywill then provide QRS synchronized atrial defibrillation/cardioversion.

The sensing circuitry utilizes the electronic signals generated from theheart and will primarily detect QRS waves. In one embodiment, thecircuitry will be programmed to detect ventricular tachycardias orfibrillations. The detection circuitry will utilize, in its most directform, a rate detection algorithm that triggers charging of a capacitoronce the ventricular rate exceeds some predetermined level for a fixedperiod of time. One trigger could be, for example, if the ventricularrate exceeds two hundred forty bpm on average for more than fourseconds. Once the capacitor is charged, a confirmatory rhythm checkwould ensure that the rate persists for at least another one secondbefore discharge. Similarly, termination algorithms could be institutedthat ensure that a rhythm less than two hundred forty bpm persisting forat least four seconds before the capacitor charge is drained to aninternal resistor. Detection, confirmation and termination algorithms asare described above and in the art can be modulated to increasesensitivity and specificity by examining QRS beat-to-beat uniformity,QRS signal frequency content, R-R interval stability data, and signalamplitude characteristics all or part of which can be used to increaseor decrease both sensitivity and specificity of S-ICD arrhythmiadetection function.

In addition to use of sense circuitry for detection of V-Fib or V-Tachby examining QRS waves, the sense circuitry can check for the presenceor the absence of respiration. The respiration rate can be detected bymonitoring the impedance across the thorax using subthreshold currentsdelivered across the active can and the high voltage subcutaneous leadelectrode and monitoring the frequency in undulation in the waveformthat results from the undulations of transthoracic impedance during therespiratory cycle. If there is no undulation, then the patent is notrespiring and this lack of respiration can be used to confirm the QRSfindings of cardiac arrest. The same technique can be used to provideinformation about the respiratory rate or estimate cardiac output asdescribed in U.S. Pat. Nos. 6,095,987, 5,423,326, 4,450,527, the entiredisclosures of which are incorporated herein by reference.

The canister of the present invention can be made out of titanium alloyor other presently preferred electrically active canister designs.However, it is contemplated that a malleable canister that can conformto the curvature of the patient's chest will be preferred. In this waythe patient can have a comfortable canister that conforms to the shapeof the patient's rib cage. Examples of conforming canisters are providedin U.S. Pat. No. 5,645,586, the entire disclosure of which is hereinincorporated by reference. Therefore, the canister can be made out ofnumerous materials such as medical grade plastics, metals, and alloys.In the preferred embodiment, the canister is smaller than sixty ccvolume having a weight of less than one hundred gms for long-termwearability. This size may have added importance in some applications,such as implantations in children. The canister and the lead of theS-ICD can also use fractal or wrinkled surfaces to increase surface areato improve defibrillation capability. Because of the primary preventionrole of the therapy and the likely need to reach energies over fortyjoules, a feature of one preferred embodiment is an extended, orintentionally long, capacitor charge time resulting in reduced energyloss and allowing use of smaller components. Examples of small ICDhousings are disclosed in U.S. Pat. Nos. 5,597,956 and 5,405,363, theentire disclosures of which are herein incorporated by reference.

Different subcutaneous electrode lead assemblies 13 of the presentinvention are illustrated in FIGS. 1-3. Turning to FIG. 1, the lead 21for the subcutaneous electrode lead assembly 13 is preferably composedof silicone or polyurethane insulation. The lead 21 is connected to thecanister 11 at its proximal end via a connection port 19 which islocated on an electrode connector block 17 of the canister 11. Theelectrode connector block 17 may be electrically isolated. The electrodelead assembly 13 illustrated includes three different electrodes 23, 25,27 secured to the lead 21. In the embodiment illustrated, an optionalanchor segment 52 is attached at the most distal end of the subcutaneouselectrode lead assembly 13 for anchoring to soft tissue such that theelectrode lead assembly 13 does not dislodge after implantation.

The most distal electrode on the subcutaneous electrode lead assemblyshown in FIG. 1 is shown as a coil electrode 27, which is used fordelivering the high voltage cardioversion/defibrillation energy acrossthe heart. The coil cardioversion/defibrillation electrode is about 5-10cm in length. Proximal to the coil electrode 27 are two sense electrodes23, 25, with a first sense electrode 25 is located proximally of thecoil electrode and a second sense electrode 23 located proximally of thefirst sense electrode 25. The sense electrodes 23, 25 are preferablyspaced far enough apart to be able to allow good QRS detection. Thisspacing can range from one to ten cm with four cm being presentlypreferred. The electrodes 23, 25 may or may not be circumferential withthe preferred embodiment. Having the sense electrodes 23, 25non-circumferential and positioned outward, toward the skin surface, isa way to minimize muscle artifact and enhance QRS signal quality. Thesensing electrodes 23, 25 are electrically isolated from the coilelectrode 27 via insulating areas 29. Similar types ofcardioversion/defibrillation electrodes are currently commerciallyavailable with transvenous configuration. For example, U.S. Pat. No.5,534,022, the entire disclosure of which is herein incorporated byreference, disclosures a composite electrode with a coilcardioversion/defibrillation electrode and sense electrodes.

Modifications to this arrangement are contemplated within the scope ofthe invention. One such modification is illustrated in FIG. 2 where thetwo sensing electrodes 25 and 23 are located distally and proximally,respectively, of the coil electrode 27. This may enable greater spacing,for example, depending on the length of the coil electrode 27, the senseelectrodes may be about six to twelve cm apart. Note also that theoptional anchor segment 52 is omitted. Further modifications of thecanister 11 are noted below.

Another electrode lead assembly modification is shown in FIG. 3, wherethe sensing electrodes 23, 25 are shown as non-circumferentialelectrodes, both being located distally of the coil electrode 27. Otherpossible electrode configurations are contemplated within the presentinvention. One example would be to omit one of the “sensing” electrodes23 or 25, and to use the coil electrode 27 as both a sensing electrodeand a cardioversion/defibrillation electrode.

It is also contemplated within the scope of the invention that thesensing of QRS waves (and transthoracic impedance) can be carried outvia sense electrodes on the canister housing or in combination with thecardioversion/defibrillation coil electrode and/or the subcutaneous leadsensing electrode(s). In this way, sensing could be performed via theone coil electrode located on the subcutaneous electrode lead assemblyand the active surface on the canister housing. Another possibilitywould be to have only one sense electrode located on the subcutaneouselectrode lead assembly and the sensing would be performed by that oneelectrode and either the coil electrode on the subcutaneous electrodelead assembly or by the active surface of the canister. The use ofsensing electrodes on the canister would eliminate the need for sensingelectrodes on the subcutaneous electrode. It is also contemplated thatthe subcutaneous electrode would be provided with at least one senseelectrode, the canister with at least one sense electrode, and ifmultiple sense electrodes are used on either the subcutaneous electrodeand/or the canister, that the best QRS wave detection combination willbe identified when the S-ICD is implanted and this combination can beselected, activating the best sensing arrangement from all the existingsensing possibilities.

Turning again to FIG. 2, two sensing electrodes 26 and 28 are located onthe electrically active surface 15 with electrical insulator rings 30placed between the sense electrodes 26, 28 and the active surface 15.These canister sense electrodes 26, 28 could be switched off andelectrically insulated during and shortly afterdefibrillation/cardioversion shock delivery. The canister senseelectrodes 26, 28 may also be placed on the electrically inactivesurface 14 of the canister 11. In the embodiment of FIG. 2, there areactually four sensing electrodes 23, 25, 26, 28: two (23, 25) on thesubcutaneous lead assembly 13 and two (26, 28) on the canister 11. Inthe preferred embodiment, the ability to change which electrodes areused for sensing would be a programmable feature of the S-ICD to adaptto changes in the patient physiology over time. The programming could bedone via the use of physical switches on the canister 11, or aspresently preferred, via the use of a programming wand or via a wirelessconnection to program the circuitry within the canister 11.

The canister 11 could be employed as either a cathode or an anode of theS-ICD cardioversion/defibrillation system. If the canister 11 is thecathode, then the subcutaneous coil electrode 27 would be the anode.Likewise, if the canister 11 is the anode, then the subcutaneous coilelectrode 27 would be the cathode.

The active canister housing will provide energy and voltage intermediateto that available with ICDs and most AEDs. The typical maximum voltagenecessary for ICDs using most biphasic waveforms is approximately 750Volts with an associated maximum energy of approximately 40 Joules. Thetypical maximum voltage necessary for AEDs is approximately 2000-5000Volts with an associated maximum energy of approximately 200-360 Joulesdepending upon the model and waveform used. The S-ICD of the presentinvention uses maximum voltages in the range of about 700 to about 3150Volts and is associated with energies of about 40 to about 210 Joules.The capacitance of the S-ICD could range from about 50 to about 200microfarads.

The sense circuitry contained within the canister 11 is highly sensitiveand specific for the presence or absence of life threatening ventriculararrhythmias. Features of the detection algorithm are programmable andthe algorithm is focused on the detection of V-FIB and high rate V-TACH(>240 bpm). Although the S-ICD of the present invention may rarely beused for an actual life-threatening event, the simplicity of design andimplementation allows it to be employed in large populations of patientsat modest risk with modest cost by non-cardiac electrophysiologists.Consequently, the S-ICD of the present invention focuses mostly on thedetection and therapy of the most malignant rhythm disorders. As part ofthe detection algorithm's applicability to children, the upper raterange is programmable upward for use in children, known to have rapidsupraventricular tachycardias and more rapid ventricular fibrillation.Energy levels also are programmable downward in order to allow treatmentof neonates and infants.

Turning now to FIG. 4, the preferred subcutaneous placement of the S-ICDof the present invention is illustrated. As would be clear to a personskilled in the art, the actual location of the S-ICD is in asubcutaneous space that is developed during the implantation process.The heart is not exposed during this process and the heart isschematically illustrated in the figures only for help in understandingwhere the canister 11 and coil electrode 27 are located with respect tothe heart. For the illustrative electrode lead assembly in FIG. 4, thesensing electrodes 23, 25 are proximal of the coil electrode 27, and twocanister sensing electrodes 26, 28 are also shown. The lead 21 of thesubcutaneous electrode lead assembly traverses in a subcutaneous patharound the thorax terminating with the (distal) coil electrode 27 at theposterior axillary line, preferably just lateral to the left scapula.This way the canister 11 and coil electrode 27 provide a reasonably goodpathway for current delivery to the majority of the ventricularmyocardium.

FIG. 5 illustrates a different placement of the present invention. TheS-ICD canister 11 is shown located in the left posterior axillary lineapproximately lateral to the tip of the inferior portion of the scapula.This location is especially useful in children. The lead 21 of thesubcutaneous electrode assembly traverses in a subcutaneous path aroundthe thorax terminating with its distal sense electrode 25 at theanterior precordial region, ideally in the inframammary crease. Here,the electrode lead assembly is shown with a distal sense electrode 25,an intermediate coil electrode 27, and a proximal sense electrode 23.

FIG. 6 illustrates the embodiment of FIG. 3 subcutaneously implanted inthe thorax with the distally located sense electrodes 23 and 25 locatedat approximately the tip of the inferior portion of the scapula, withthe more proximally located coil electrode 27 located at approximatelythe left axillary line.

FIG. 7 schematically illustrates the method for implanting the S-ICD ofthe present invention. An incision 31 is made in the left anterioraxillary line approximately at the level of the cardiac apex. Thisincision location is selected specifically to allow both canisterlocation more medially in the left inframammary crease and leadpositioning more posteriorly via the introducer set (described below)around to the left posterior axillary line lateral to the left scapula.The incision can be anywhere on the thorax deemed reasonable by theimplanting physician, but is preferably located as illustrated. Asubcutaneous pocket and pathway 33 is then created medially along theinframammary crease for the canister and posteriorly to the leftposterior axillary line, then toward the left scapula for the lead.

The S-ICD canister is then placed subcutaneously at the location of theincision or medial of the incision in the subcutaneous region along theleft inframammary crease. The electrode lead assembly is placedsubcutaneously with a specially designed curved introducer set 40, anillustrative example of which is shown in FIG. 8. The introducer setcomprises a curved trocar 42 and a stiff curved peel away sheath 44. Thepeel away sheath 44 is curved to allow for placement around the rib cageof the patient in the subcutaneous space created by the trocar 42. Thesheath 44 has to be stiff enough to allow for the placement of theelectrode lead assembly without the sheath 44 collapsing, kinking, orbending. Preferably the sheath 44 is made out of a biocompatible plasticmaterial and is perforated along its axial length to allow for it tosplit apart into two sections. The trocar 42 has a proximal handle 41and a curved shaft 43. The distal end 45 of the trocar 42 is tapered toallow for dissection of a subcutaneous path 33 in the patient.Preferably, the trocar 42 has a central lumen 46 that terminates in anopening 48 at the distal end 45. Local anesthetic such as lidocaine canbe delivered, if desired, through the lumen 46 or through a curved andelongated needle (not shown) designed to anesthetize the path to be usedfor trocar insertion should general anesthesia not be employed. Thecurved peel away sheath 44 has a proximal pull tab 49 for breaking thesheath into two halves along its axial shaft 47. The sheath 44 is placedover a guidewire (not shown) inserted through the trocar 42 after thesubcutaneous path has been created and developed until it terminatessubcutaneously at a location that, if a straight line were drawn fromthe canister location to the path termination point, the line wouldintersect a substantial portion of the left ventricular mass of thepatient. The guidewire is then removed leaving the peel away sheath 44.

The subcutaneous electrode lead assembly is then inserted through thesheath until it is in the proper location. Once the subcutaneouselectrode lead assembly is in the proper location, the peel away sheath44 is split in half using the pull tab 49 and removed. If more than onesubcutaneous electrode lead assembly is being used, a new curved peelaway sheath 44 can be used for each subcutaneous electrode leadassembly.

The S-ICD will have prophylactic use in adults where chronictransvenous/epicardial ICD lead systems pose excessive risk or havealready resulted in difficulty, such as sepsis or lead fractures. It isalso contemplated that a major use of the S-ICD system of the presentinvention will be for prophylactic use in children who are at risk forhaving fatal arrhythmias, where chronic transvenous lead systems posesignificant management problems. For example, with the use of standardtransvenous ICDs in children, problems develop during patient growth inthat the lead system does not accommodate the growth.

FIG. 9 illustrates the placement of the S-ICD subcutaneous lead systemsuch that several problems that growth presents to the lead system areovercome. The distal end of the subcutaneous electrode is placed in thesame location as described above providing a good location for the coilcardioversion/defibrillation electrode 27 and the sensing electrodes 23and 25. Again, the canister 11 is placed medial of a portion of theinsulated lead 21. The insulated lead 21, however, is no longer placedin a straight configuration. Instead, the lead is serpiginously placedwith a specially designed introducer trocar and sheath such that it hasnumerous waves or bends. As the child grows, the waves or bends willstraighten out, straightening the lead system while maintaining properelectrode placement. Although it is expected that fibrous scarringespecially around the coil electrode 27 will help anchor it intoposition to maintain its posterior position during growth, a lead systemwith a distal tine or screw electrode anchoring system 52 can also beincorporated into the distal tip of the lead to facilitate leadstability (see FIG. 1). Other anchoring systems can also be used such ashooks, sutures, or the like.

FIGS. 10 and 11 illustrate another embodiment of the present S-ICDinvention. In this embodiment there are two subcutaneous electrode leadassemblies 13 and 13′ of opposite polarity to the canister 11. Theadditional subcutaneous electrode lead assembly 13′ can take any of theforms illustrated above for electrode lead assembly 13. In thisembodiment the cardioversion/defibrillation energy is delivered betweenthe active surface 15 of the canister 11 and the two coil electrodes 27and 27′. Additionally, provided in the canister 11 is means forselecting the optimum sensing arrangement between the four senseelectrodes 23, 23′, 25, and 25′. The two electrode lead assemblies maybe subcutaneously placed on the same side of the heart. As illustratedin FIG. 11, one subcutaneous electrode lead assembly 13 is placedinferiorly and the other electrode lead assembly 13′ is placedsuperiorly. Alternatively, a dual subcutaneous lead assembly system mayhave the canister 11 and one of the electrode lead assemblies 13, 13′having the same polarity, with the other of the electrode leadassemblies 13′, 13, having the opposite polarity. While the exampleplacement of FIG. 11 shows the canister 11 placed in a posteriorposition, the canister 11 may also be placed in an anterior position asshown above in FIG. 6, with the electrode lead assemblies inserted forplacement of the electrodes in an anterior position.

Turning now to FIGS. 12 and 13, further embodiments are illustratedwhere a canister 11 is shaped for placing subcutaneously adjacent andparallel to a rib of a patient. The canister 11 is long, thin, andcurved to conform to the shape of the patient's rib. In the embodimentillustrated in FIG. 12, the canister 11 has a diameter ranging fromabout 0.5 cm to about two cm with about one cm being presentlypreferred. Alternatively, instead of having a circular cross sectionalarea, the canister 11 could have a rectangular or square cross sectionalarea as illustrated in FIG. 13 without falling outside of the scope ofthe present invention. The length of the canister 11 can vary dependingon the size of the patient's thorax. In some present embodiments, thecanister 11 is about five cm to about fifteen cm long, with about ten cmbeing presently preferred. The canister 11 is curved to conform to thecurvature of the ribs of the thorax. The radius of the curvature willvary depending on the size of the patient, with smaller radiuses forsmaller patients and larger radiuses for larger patients. The radius ofthe curvature can range from about five cm to about thirty-five cmdepending on the size of the patient. Additionally, the radius of thecurvature need not be uniform throughout the canister such that it canbe shaped closer to the shape of the ribs. The canister 11 has an activesurface 15 that is located on the interior (concave) portion of thecurvature and an inactive surface 16 that is located on the exterior(convex) portion of the curvature. The leads of these embodiments, whichare not illustrated except for the attachment port 19 and the proximalend of the lead 21, can be any of the leads previously described above,with the lead illustrated in FIG. 1 being presently preferred.

The circuitry of this canister 11 is similar to the circuitry describedabove. Additionally, the canister 11 can optionally have at least onesense electrode located on either the active surface 15 or the inactivesurface 16 and the circuitry within the canister 11 can be programmableas described above to allow for the selection of the best senseelectrodes. It is presently preferred that the canister 11 have twosense electrodes 26, 28 located on the inactive surface 16 of thecanister 11 as illustrated, where the electrodes 26, 28 are spaced fromabout one to about ten cm apart with a spacing of about three cm beingpresently preferred. Alternatively, the sense electrodes 26, 28 can belocated on the active surface 15 as described above.

It is envisioned that the embodiment of FIG. 12 will be subcutaneouslyimplanted adjacent and parallel to the left anterior 5th rib, eitherbetween the 4th and 5th ribs or between the 5th and 6th ribs. Howeverother locations can be used.

Another component of the S-ICD of the present invention is a cutaneoustest electrode system designed to simulate the subcutaneous high voltageshock electrode system as well as the QRS cardiac rhythm detectionsystem. This test electrode system is comprised of a cutaneous patchelectrode of similar surface area and impedance to that of the S-ICDcanister itself together with a cutaneous strip electrode comprising adefibrillation strip as well as two button electrodes for sensing of theQRS. Several cutaneous strip electrodes are available to allow fortesting various bipole spacings to optimize signal detection comparableto the implantable system.

FIGS. 14 to 18 depict several US-ICD (unitary subcutaneous implantablecardioverter/defibrillator) embodiments of the present invention. Thevarious sensing, shocking and pacing circuitry, described in detailabove with respect to the S-ICD embodiments, may additionally beincorporated into the following US-ICD embodiments. Furthermore,particular aspects of any individual S-ICD embodiments discussed abovemay be incorporated, in whole or in part, into the US-ICD embodimentsdepicted in the following figures.

Turning now to FIG. 14, a US-ICD of the present invention isillustrated. The US-ICD includes a curved housing 1211 with a first end1413 and a second end 1215. The first end 1413 is thicker than thesecond end 1215. This thicker area houses a battery supply, capacitorand operational circuitry for the US-ICD. The circuitry will be able tomonitor cardiac rhythms for tachycardia and fibrillation, and ifdetected, will initiate charging the capacitor and then deliveringcardioversion/defibrillation energy through twocardioversion/defibrillating electrodes 1417 and 1219 located on theouter surface of the two ends of the housing. The circuitry can providecardioversion/defibrillation energy in different types of waveforms. Inthe preferred embodiment, a biphasic waveform is used of approximately10-20 ms total duration and with the initial phase containingapproximately ⅔ of the energy, however, any type of waveform can beutilized such as monophasic, biphasic, multiphasic or alternativewaveforms known in the art.

The housing of the illustrative embodiment can be made out of titaniumalloy, for example, or other materials. It is contemplated that thehousing may also be made out of biocompatible plastic materials thatelectrically insulate the electrodes 1219, 1417 from each other.However, it is contemplated that a malleable canister that can conformto the curvature of the patient's chest will be preferred. In this waythe patient can have a comfortable canister that conforms to the uniqueshape of the patient's rib cage. Examples of conforming ICD housings areprovided in U.S. Pat. No. 5,645,586, the entire disclosure of which isherein incorporated by reference. In the preferred embodiment, thehousing is curved in the shape of a 5^(th) rib of a person. Becausethere are many different sizes of people, the housing may come indifferent incremental sizes to allow a good match between the size ofthe rib cage and the size of the US-ICD. The length of the US-ICD willrange from about fifteen to about fifty cm. Because of the primarypreventative role of the therapy and the need to reach energies overforty Joules, in the preferred embodiment, the charge time for thetherapeutic shock is intentionally long in order to allow capacitorcharging using components that fit within the limitations of devicesize.

The thick end 1412 of the housing 1211 is currently needed to allow forthe placement of the battery supply, operational circuitry, andcapacitors. It is contemplated that the thick end 1412 will be about 0.5cm to about two cm wide with about one cm being presently preferred. Asmicro technology advances, the thickness of the housing 1211 will becomesmaller.

The two cardioversion/defibrillation electrodes 1219, 1417 on thehousing 1211 are used for delivering cardioversion/defibrillation energyacross the heart. In the preferred embodiment, the electrodes 1219, 1417are coil electrodes. However, other cardioversion/defibrillationelectrodes could be used, for example, using electrically isolatedactive surfaces or platinum alloy electrodes. The coil electrodes 1219,1417 are about five to ten cm in length. Located on the housing betweenthe two cardioversion/defibrillation electrodes 1219, 1417 are two senseelectrodes 1425, 1427. The sense electrodes 1425, 1427 are spaced farenough apart to be able to have good QRS detection. This spacing canrange from one to ten cm with four cm being presently preferred. Theelectrodes 1425, 1427 may or may not be circumferential with thepreferred embodiment. Having the electrodes 1425, 1427non-circumferential and positioned outward, toward the skin surface, mayreduce muscle artifacts and enhance QRS signal quality. The sensingelectrodes 1425, 1427 are electrically isolated from thecardioversion/defibrillation electrodes 1219, 1417 via insulating areas1423. Analogous types of cardioversion/defibrillation electrodes arecurrently commercially available in a transvenous configuration. Forexample, U.S. Pat. No. 5,534,022, the entire disclosure of which isherein incorporated by reference, discloses a composite electrode with acoil cardioversion/defibrillation electrode and sense electrodes.

Several modifications to the arrangement of FIG. 14 are contemplatedwithin the scope of the invention. One such modification is to have thesense electrodes 1425, 1427 at the two ends of the housing 1211 and havethe cardioversion/defibrillation electrodes 1219, 1417 located inbetween the sense electrodes 1425, 1427. Another modification is to havethree or more sense electrodes spaced throughout the housing 1211 andallow for the selection of the two best sensing electrodes. If three ormore sensing electrodes are used, then the ability to change whichelectrodes are used for sensing would be a programmable feature of theUS-ICD to adapt to changes in the patient physiology and size over time.The programming could be done via the use of physical switches on thecanister, or as presently preferred, via the use of a programming wandor via a wireless connection to program the circuitry within thecanister.

Turning now to FIG. 15, a preferred subcutaneous placement of the US-ICDof the present invention is illustrated. As would be evident to a personskilled in the art, the actual location of the US-ICD is in asubcutaneous space that is developed during the implantation process.The heart is not exposed during this process and the heart isschematically illustrated in the figures only for help in understandingwhere the device and its various electrodes are located with referenceto the heart. The US-ICD housing 1211 is shown located between the leftmid-clavicular line approximately at the level of the inframammarycrease at approximately the 5^(th) rib and the posterior axillary line,ideally just lateral to the left scapula. This way the US-ICD provides areasonably good pathway for current delivery to the majority of theventricular myocardium.

FIG. 16 schematically illustrates the method for implanting the US-ICDof the present invention. An incision 1631 is made in the left anterioraxillary line approximately at the level of the cardiac apex. Asubcutaneous pathway is then created that extends posteriorly to allowplacement of the US-ICD. The incision can be anywhere on the thoraxdeemed reasonable by the implanting physician although in the preferredembodiment, the US-ICD of the present invention will be applied in thisregion. The subcutaneous pathway is created medially to the inframammarycrease and extends posteriorly to the left posterior axillary line. Thepathway is preferably developed with a specially designed curvedintroducer 1742 (further illustrated below in FIG. 17).

Referring now to FIG. 17, introducer 1742 is a trocar having a proximalhandle 1641 and a curved shaft 1643. The distal end 1745 of theintroducer 1742 is tapered to allow for dissection of a subcutaneouspath in the patient. Preferably, the introducer 1742 is cannulatedhaving a central lumen 1746 and terminating in an opening 1748 at thedistal end 1745. Local anesthetic such as lidocaine can be delivered, ifnecessary, through the lumen 1746 or through a curved and elongatedneedle designed to anesthetize the path to be used for trocar insertion,if general anesthesia is not employed. Once the subcutaneous pathway isdeveloped, the US-ICD is implanted in the subcutaneous space, and theincision is closed using standard techniques.

As described previously, the US-ICDs of the present invention vary inlength and curvature. The US-ICDs are provided in incremental sizes forsubcutaneous implantation in different sized patients. Turning now toFIG. 18, a different embodiment is schematically illustrated in explodedview which provides different sized US-ICDs that are easier tomanufacture. The different sized US-ICDs will all have the same sizedand shaped thick end 1413. The thick end is hollow inside allowing forthe insertion of a core operational member 1853. The core membercomprises a housing 1857 which contains the battery supply, capacitorand operational circuitry for the US-ICD. The proximal end of the coremember has a plurality of electronic plug connectors. Plug connectors1861 and 1863 are electronically connected to the sense electrodes viapressure fit connectors (not illustrated) inside the thick end which arestandard in the art. Plug connectors 1865 and 1867 are alsoelectronically connected to the cardioverter/defibrillator electrodesvia pressure fit connectors inside the thick end. The distal end of thecore member comprises an end cap 1855, and a ribbed fitting 1859 whichcreates a water-tight seal when the core member is inserted into opening1851 of the thick end of the US-ICD.

The core member of the different sized and shaped US-ICD will all be thesame size and shape. That way, during an implantation procedure,multiple sized US-ICDs can be available for implantation, each onewithout a core member. Once the implantation procedure is beingperformed, then the correct sized US-ICD can be selected and the coremember can be inserted into the US-ICD and then programmed as describedabove. Another advantage of this configuration is when the batterywithin the core member needs replacing it can be done without removingthe entire US-ICD.

FIG. 19( a) illustrates an embodiment of the subcutaneous lead electrodeor “lead electrode assembly” 100. The lead electrode assembly 100 isdesigned to provide an electrode 107 to be implanted subcutaneously inthe posterior thorax of a patient for delivery ofcardioversion/defibrillation energy. The lead electrode assembly 100 isfurther designed to provide a path for the cardioversion/defibrillationenergy to reach the electrode 107 from the operational circuitry withinthe canister 11 of an S-ICD such as the embodiment in FIG. 1.

The lead electrode assembly 100 comprises a connector 111, a lead 21, alead fastener 146, an electrode 107 and an appendage 118. The connector111 is connected to the lead 21. The lead 21 is further connected to theelectrode 107 with the lead fastener 146. The appendage 118 is mountedto the electrode 107.

The connector 111 provides an electrical connection between the lead 21and the operational circuitry within the canister 11 of an S-ICD such asthe embodiment shown in FIG. 1. Connector 111 is designed to mate withthe connection port 19 (FIG. 1) on the canister 11 (FIG. 1). In theembodiment under discussion, the connector 111 preferably meets the IS-1standard.

The lead 21 of the lead electrode assembly 100 provides an electricalconnection between the connector 111 and the electrode 107. The lead 21comprises a proximal end 101 and a distal end 102. The proximal end 101of the lead 21 is attached to the connector 111. The distal end 102 ofthe lead 21 is attached to electrode 107 with the lead fastener 146.

The lead 21 has a lead length, l_(LEAD), measured from the connector 111along the lead 21 to the lead fastener 146 of the electrode 107. Thelength of the lead 21 is approximately twenty-five cm. In alternativeembodiments, the lead lengths range between approximately five andapproximately fifty-two cm. The lead fastener 146 provides a robustphysical and electrical connection between the lead 21 and the electrode107. The lead fastener 146 joins the distal end 102 of the lead 21 tothe electrode 107.

The electrode 107 comprises an electrically conductive member designedto make contact with the tissue of the patient and transfercardioversion/defibrillation energy to the tissue of the patient fromthe S-ICD canister 11. The electrode 107 illustrated is generally flatand planar, comprising a top surface 110, a bottom surface 115, aproximal end 103 and a distal end 104. The lead fastener 146 is attachedto the top surface 110 of the proximal end 103 of the electrode 107. Insome embodiments, the electrode 107 may have shapes other than planar.In another embodiment, the electrode 107 is shaped like a coil.

The appendage 118 is a member attached to the electrode 107 that can begripped and used to precisely locate the lead electrode assembly 100during its surgical implantation within the patient. The appendage 118has a first end 105, a second end 106, a proximal edge 121 and a distaledge 129. The second end 106 of the appendage 118 is attached to the topsurface 110 of the electrode 107. The appendage 118 is positioned suchthat its distal edge 129 is within approximately twenty mm of the distalend 104 of the electrode 107. In alternate embodiments, the appendage118 is attached to the electrode 107 in other positions.

It is useful at this point, to set out several general definitions forfuture reference in discussing the dimensions and placement theappendage 118. The appendage height, h_(APPENDAGE), is defined as thedistance from the point of the appendage 118 most distant from theelectrode 107 to a point of the appendage 118 closest to the electrode107 measured along a line perpendicular to the top surface 110 of theelectrode 107. The appendage height h_(APPENDAGE) of the appendage 118illustrated, for example, would be measured between the first end 105 ofthe appendage 118 and the second end 106 of the appendage 118. Theappendage height of the appendage 118 illustrated would be approximatelyfive mm. In alternative embodiments, the appendage heights range betweenapproximately one and approximately ten mm.

The appendage interface is defined as the part of the appendage 118 thatjoins it to the electrode 107. The appendage interface of the appendage118 illustrated, for example, would be the second end 106 of theappendage 118. The appendage length, l_(APPENDAGE), is the length of theappendage 118 along the appendage interface. The appendage interface ofthe appendage 118 illustrated, for example, would be the length of thesecond end 106 of the appendage 118. The appendage length of theappendage 118 illustrated in FIG. 19( a) is approximately one cm. Inalternative embodiments, appendage lengths range between approximatelytwo mm and approximately six cm. In an alternate embodiment, theappendage 118 is substantially as long as the electrode 107.

More particularly, the appendage 118 of the embodiment illustrated is afin 120 comprising a fin core 122 (phantom view) and a coating 125. Thefin core 122 generally provides support for the fin 120. The fin core122 has a first end 126 and a second end 127. The second end 127 of thefin core 122 is attached to the top surface 110 of the electrode 107.The fin core 122 comprises a metal such as titanium, nickel alloys,stainless steel alloys, platinum, platinum iridium, and mixturesthereof. In other embodiments, the fin core 122 comprises any ruggedmaterial that can be attached to the first surface 110 of the electrode107.

The coating 125 is disposed around the fin core 122. The coating 125provides a surface for the fin 120 that can be easily gripped during theimplantation of the lead electrode assembly 100. The coating 125covering the fin core 122 is composed of molded silicone. In otherembodiments, the coating 125 may be any polymeric material. In oneembodiment, the fin 120 is reinforced with a layer of Dacron® polymermesh attached to the inside of the coating 125. Dacron® is a registeredtrademark of E.I. du Pont de Nemours and Company Corporation,Wilmington, Del. In another embodiment, the Dacron® polymer mesh isattached to the outside of the coating 125. In another embodiment, thefin 120 is reinforced with a layer of any polymeric material.

FIG. 19( b) illustrates a top view of the lead electrode assembly ofFIG. 19( a). The electrode 107 is substantially rectangular in shape,comprising a first pair of sides 108, a second pair of sides 109 andfour corners 112. In an alternative embodiment the electrode 107 has ashape other than rectangular. In this embodiment, the corners 112 of theelectrode 107 are rounded. In an alternative embodiment the corners 112of the electrode 107 are not rounded.

The first pair of sides 108 of the electrode 107 are substantiallylinear, substantially parallel to each other and are approximately onecm in length. The second pair of sides 109 of the electrode 107 are alsosubstantially linear, substantially parallel with each other and areapproximately five cm in length. The bottom surface 115 of the electrode107 has an area of approximately five hundred square mm. In alternativeembodiments, the first pair of sides 108 and the second pair of sides109 of the electrode 107 are neither linear nor parallel.

In alternative embodiments, the length of the first pair of sides 108and second pair of sides 109 of the electrode 107 range independentlybetween approximately one cm and approximately five cm. The surface areaof the bottom surface 115 of the electrode 107 ranges betweenapproximately one hundred square mm and approximately two thousandsquare mm. In another embodiment, the first pair of sides 108 and secondpair of sides 109 of the electrode 107 are linear and of equal length,such that the electrode 107 is substantially square-shaped.

The electrode 107 comprises a sheet of metallic mesh 114 furthercomprised of woven wires 119. The metallic mesh 114 comprises a metalselected from the group consisting essentially of titanium, nickelalloys, stainless steel alloys, platinum, platinum iridium, and mixturesthereof. In other embodiments, the metallic mesh 114 comprises anyconductive material. In an alternate embodiment, the electrode 107comprises a solid metallic plate. The metallic plate maybe formed, forexample, of titanium, nickel alloys, stainless steel alloys, platinum,platinum iridium, and mixtures thereof, as well as any other conductivematerial.

The metallic mesh 114 is approximately a one hundred fifty mesh, havingapproximately one hundred fifty individual wires 119 per inch. Inalternative embodiments, the metallic mesh 114 ranges betweenapproximately a fifty mesh and approximately a two hundred mesh. In thisembodiment, the diameter of the wires 119 of the mesh is approximatelyone mil. In alternative embodiments, the diameter of the wires 119ranges between approximately one and approximately five mils.

The metallic mesh 114 is first prepared by spot welding together thewires 119 located along the first pair of sides 108 and second pair ofsides 109 of the metallic mesh 114. The excess lengths of wires are thenground or machined flush, so as to produce a smooth edge and to form asmooth border 113. In an alternate embodiment, the wires 119 locatedalong the first pair of sides 108 and second pair of sides 109 of themetallic mesh 114 are bent in toward the metallic mesh 114 to form asmooth border 113.

The fin 120 is attached to the top surface 110 of the electrode 107 in aposition centered between the first pair of sides 108 of the electrode107. In other embodiments, the fin 120 is not centered between the firstpair of sides 108 of the electrode 107.

The fin 120 is planar shape comprising a first face 191 and a secondface 192. The first face 191 and the second face 192 of the fin 120 aresubstantially parallel to the first pair of sides 108 of the electrode107. In other embodiments, the first face 191 and the second face 192 ofthe fin 120 are positioned in orientations other than parallel to thefirst pair of sides 108 of the electrode 107.

The first face 191 and the second face 192 of the fin 120 extend fromand substantially perpendicular to the top surface 110 of the electrode107. In an alternative embodiment, the first face 191 and the secondface 192 of the fin 120 extend from the top surface 110 of the electrode107 at other than right angles. The fin core 122 of the fin 120 is spotwelded to the metallic mesh 114 comprising the electrode 107. In anotherembodiment, the fin 120 may be composed entirely of a polymeric materialand attached to the electrode 107 by means known in the art.

FIG. 19( c) illustrates in detail a section of the lead 21 of theembodiment of FIGS. 19( a)-19(b). The lead 21 comprises an electricallyinsulating sheath 141 and an electrical conductor 142. The electricallyinsulating sheath 141 is disposed around the electrical conductor 142(phantom view). The electrically insulating sheath 141 prevents thecardioversion/defibrillation energy passing through the electricalconductor 142 to the electrode from passing into objects surrounding thelead 21. The electrically insulating sheath 141 comprises a tube 149disposed around the electrical conductor 142. The tube 149 is composedof silicone, polyurethane or composite materials. One skilled in the artwill recognize that the tube 149 could alternately be composed of anyinsulating, flexible, biocompatible material suitable to this purpose.

In this embodiment, the electrical conductor 142 comprises three highlyflexible, highly conductive coiled fibers known as filars 147 (phantomview). These fibers are wound in a helical shape through theelectrically insulating sheath 141. In an alternate embodiment, thefilars 147 lie as linear cables within the electrically insulatingsheath 141. In another alternate embodiment, a combination of helicallycoiled and linear filars 147 lie within the electrically insulatingsheath 141.

FIG. 19( d) illustrates a cross-section of a filar 147. The filars 147of the embodiment illustrated comprise a metal core 144, a metal tube143 and an insulating coating 140. The metal tube 143 is disposed aroundthe metal core 144. The insulating coating 140 is disposed around themetal tube. The metal core 144 is made of silver and the metal tube 143is made of MP35N® stainless steel, a product of SPS Technologies ofJenkintown, Pa. The insulating coating 140 is made of Teflon. The filars147 of this structure are available as DFT® (drawn filled tube)conductor coil, available from Fort Wayne Metals Research Products Corp.of Fort Wayne, Ind.

In an alternative embodiment, the filars 147 further comprise anintermediate coating (not shown) disposed between the metal tube 143 andthe insulating coating 140. This intermediate coating is made ofplatinum, iridium, ruthenium, palladium or an alloy of these metals. Inanother alternative embodiment, the filars 147 comprise DBS® (drawnbraised strands) also available from Fort Wayne Metals Research ProductsCorp. of Fort Wayne, Ind.

Turning now to FIG. 19( e), a cross section of the lead fastener 146 isshown in detail. The lead fastener 146 provides a robust physical andelectrical connection between the lead 21 and the electrode 107. In thisembodiment, the lead fastener 146 comprises a metal strip 157, acrimping tube 154 and a crimping pin 156. The metal strip 157 has afirst end 150, a second end 151, and a middle portion 152. The first end150 and second end 151 of the metal strip 157 are separated by themiddle portion 152. The first end 150 and second end 151 of the metalstrip 157 are attached to the electrode 107. In this embodiment, thefirst end 150 and second end 151 of the lead fastener 146 are spotwelded to the top surface 110 of the metallic mesh 114 of the electrode107. In other embodiments, other fastening methods known in the art canbe used.

The middle portion 152 of the metal strip 157 is raised away from theelectrode 107 to permit the crimping tube 154 and electricallyinsulating sheath 141 of the lead 21 to fit between the metal strip 157and the electrode 107. The middle portion 152 of the metal strip 157contains a crimp point 148. The crimp point 148 squeezes the crimpingtube 154 and electrically insulating sheath 141 of the lead 21 therebygripping it, and thereby providing a robust structural connectionbetween the lead 21 and the electrode 107.

The filars 147 of the lead 21 are situated between the crimping tube 154and crimping pin 156. The crimping tube 154 has a crimping point 155which causes the filars 147 to be squeezed between crimping tube 154 andcrimping pin 156. A gap 159 in the electrically insulating sheath 141allows the crimping tube 155 to make contact with the electrode 107,thereby forming a robust electrical connection.

The metal strip 157, the crimping tube 154 and crimping pin 156 are eachmade of platinum iridium. In alternative embodiments, the metal strip157, crimping tube 154 and crimping pin 156 are each made of a metalsuch as titanium, nickel alloys, stainless steel alloys, platinum,platinum iridium, and mixtures thereof. In an alternative embodiment,the metal strip 157, crimping tube 154 and crimping pin 156 are eachmade of any conductive material. FIG. 19( f) illustrates an explodedview of the lead fastener 146. In other embodiments, other types of leadfasteners 146 known in the art are used.

FIG. 20( a) illustrates an alternative embodiment of the lead electrodeassembly 100. This embodiment is substantially similar to the leadelectrode assembly 100 illustrated in FIGS. 19( a)-19(f). In thisembodiment, however, the appendage 118 lacks a fin core. Moreover, asseen in FIG. 20( a) the lead electrode assembly 100 of this embodimentfurther comprises a backing layer 130 and stitching 139. The backinglayer 130 acts to insulate the electrode 107 so thatcardioversion/defibrillation energy may not pass to the tissue of thepatient that surrounds the top surface 110 of the electrode 107. Thishas the effect of focusing the cardioversion/defibrillation energytoward the heart of the patient through the bottom surface 115 of theelectrode 107.

The backing layer 130 comprises a base portion 158 and an integrated fin120. The base portion 158 of the backing layer 130 comprises a firstsurface 131, a second surface 132, a first side 133 and a second side134. The base portion 158 of the backing layer 130 is attached to theelectrode 107 such that the second surface 132 of the backing layer 130lies directly adjacent to the top surface 110 of the electrode 107. Thebase portion 158 of the backing layer 130 is formed so that the firstside 133 and the second side 134 are substantially parallel and ofsubstantially the same size as the first pair of sides 108 of theelectrode 107.

FIG. 20( b) illustrates a top view of the lead electrode assembly 100 ofthis embodiment. The base portion of the backing layer 130 furthercomprises a proximal end 137 and a distal end 138. The proximal end 137and distal end 138 of the backing layer 130 are parallel to and ofsubstantially the same size as the second pair of sides 109 (hidden) ofthe electrode 107. The backing layer 130 contains a notch 136 on itsproximal end 137, through which the lead fastener rises. The baseportion 158 of the backing layer 130 is attached to the electrode 107with stitching 139. The stitching is composed of nylon. In alternateembodiments, the stitching is composed of any polymeric material.

In one embodiment, the backing layer 130 is composed of polyurethane. Inan alternative embodiment, the backing layer is composed of moldedsilicone, nylon, or Dacron®. In alternative embodiments, the backinglayer 130 is composed of any polymeric material. The integrated fin 120of the backing layer 130 is formed from the same piece of material asthe backing layer 130. The integrated fin 120 has the same shape anddimensions as the fin 120 of the embodiment in FIG. 19( a). In oneembodiment, the integrated fin 120 is reinforced with a layer of Dacron®polymer mesh attached to the integrated fin 120. In another embodiment,the integrated fin 120 is reinforced with a layer of any polymericmaterial.

FIG. 21 illustrates an alternative embodiment of the lead electrodeassembly 100. This embodiment is substantially similar to the leadelectrode assembly 100 illustrated in FIGS. 19( a)-19(e). In thisembodiment, however, the fin 120 has a different construction. Here, fin120 comprises a first fin section 165, a second fin section 160 andstitching 168. The first fin section 165 is a rectangular sheet ofpolymeric material comprising an inside face 167, an outside face 166, afirst side 175 and a second side 174. The first side 175 and second side174 of the first fin section 165 are substantially parallel and ofsubstantially the same size.

A line 173 divides the first fin section 165 into a first half 171 and asecond half 172. The line 173 runs parallel to the first side 175 of thefirst fin section 165. The first half 171 of the first fin section 165lies on one side of line 173. The second half 172 of the first finsection 165 lies on the other side of the line 173. The second finsection 160 is a rectangular sheet of polymeric material of the samesize as the first fin section 165 comprising an inside face 162 and anoutside face 161. The second fin section 160 is divided in halfsubstantially similarly to the first fin section 165, thereby forming afirst half 163 and a second half 164 of the second fin section 160. Inan alternate embodiment, the first fin section 165 and second finsection are not rectangular in shape. In an alternate embodiment, thefirst fin section 165 and second fin section 160 have an oval shape.

The first half 171 of the first fin section 165 is fastened to the firsthalf 163 of the second fin section 160. The inside face 167 of the firsthalf 171 of the first fin section 165 faces the inside face 162 of thefirst half 163 of the second fin section 160. The first fin section 165is fastened the second fin section 160 with stitching 168. The fin 120is attached to the top surface 110 of the electrode 107. To accomplishthis, the second half 172 of the first fin section 165 is attached tothe top surface 110 of the electrode 107 with the stitching 169. Thesecond half 164 of the second fin section 160 is similarly attached tothe top surface 110 of the electrode 107 with stitching (not shown).

In one embodiment, the fin 120 is reinforced with a layer of Dacron®polymer mesh positioned between the first fin section 165 and the secondfin section 160 of the integrated fin 120. In another embodiment, theDacron® polymer mesh is attached only to the first fin section 165 orthe second fin section 160. In other embodiments, the integrated fin 120is reinforced with a layer of any polymeric material attached to eitheror both fin sections.

The appendage height of the fin 120 in this embodiment is approximatelyfive mm. In alternative embodiments, the appendage heights range betweenapproximately one mm and approximately ten mm. The appendage length ofthe fin 120 in this embodiment is approximately one cm. In alternativeembodiments, appendage lengths range between approximately two mm andapproximately six cm. In one embodiment, the appendage length of the fin120 is such that the fin 120 is substantially as long as the electrode107.

FIG. 22( a) illustrates a side plan view of an alternative embodiment ofthe lead electrode assembly 100. The lead electrode assembly 100comprises a connector 111, a lead 21, a lead fastener 146, an electrode107, a backing layer 130 with an integrated fin tab 180, a molded cover220 and an appendage 118.

The connector 111 is connected to the lead 21. The lead 21 is furtherconnected to the electrode 107 with the lead fastener 146. The backinglayer 130 is positioned over the electrode 107. The fin tab 180protrudes from the backing layer 130. The molded cover 220 is disposedaround the lead fastener 146 and the backing layer 130. The molded cover220 is further disposed around the fin tab 180 of the backing layer 118to form the appendage 118. The molded cover 220 also partially envelopsthe electrode 107.

The connector 111 and the lead 21 are substantially similar to theconnector 111 and the lead 21 described with reference to FIGS. 19(a)-19(f). The lead comprises a proximal end 101 and a distal end 102.The proximal end 101 of the lead 21 is attached to the connector 111.The distal end 102 of the lead 21 is connected to the electrode 107 bythe lead fastener 146.

In this embodiment, the lead fastener 146 comprises a first crimpingtube 200, a crimping pin 202 and a second crimping tube 201. The firstcrimping tube 200 connects the distal end 102 of the lead 21 to thecrimping pin 202. The second crimping tube 201 connects the crimping pin202 to the electrode 107. The electrode 107 comprises a proximal end 103(phantom view), a distal end 104, a top surface 110 and a bottom surface115. The electrode further comprises three sections: a main body 217, amandrel 219 and a mandrel neck 218.

The main body 217 of the electrode 107 is the region of the electrode107 that makes contact with the tissue of the patient and transfers thecardioversion/defibrillation energy to the patient. This region issubstantially rectangular, comprising a first pair of sides 108 (notshown) and a second pair of sides 109. The first pair of sides 108 ofthe electrode 107 are substantially parallel to each other. The secondpair of sides 109 of the electrode 107 are also substantially parallelto each other. In another embodiment, the first pair of sides 108 andthe second pair of sides 109 of the electrode 107 are non-parallel. Themain body 217 of the electrode 107 is positioned under the backing layer130, so that the top surface 110 of the electrode faces the backinglayer 130.

The mandrel 219 is a region of the electrode 107 shaped to facilitatethe connection of the electrode 107 to the lead 21 via the lead fastener146. The mandrel 219 of the electrode is crimped onto to the crimpingpin 202 of the lead fastener 146 with the second crimping tube 201, sothat a robust physical and electrical connection is formed. The mainbody 217 of the electrode 107 is connected to the mandrel 219 of theelectrode 107 via the mandrel neck 218 of the electrode 107. The backinglayer 130 comprises a base portion 158 and an integrated fin tab 180.The base portion 158 of the backing layer 130 comprises a first surface131, a second surface 132, a proximal end 137 and a distal end 138.

The base portion 158 of the backing layer 130 is positioned such thatits second surface 132 is adjacent to the top surface 110 of theelectrode 107. The base portion 158 of the backing layer 130 is sizedand positioned so that the proximal end 137 and distal end 138 of thebase portion 158 of the backing layer 130 overlay the second pair ofsides 109 of the main body 217 of the electrode 107. The proximal end137 and distal end 138 of the base portion 158 are also substantiallyparallel and of substantially the same size as the second pair of sides109 of the electrode 107.

The integrated fin tab 180 of the backing layer 130 is formed from thesame piece of material as the base portion 158 of the backing layer 130.The integrated fin tab 180 is formed on the first surface 131 of thebase portion 158 of the backing layer 130.

The integrated fin tab 180 comprises a proximal edge 184, a distal edge183, a top 185 and a bottom 186. The bottom 186 of the integrated fintab 180 is joined to the first surface 131 of the base portion 158 ofthe backing layer 130. The proximal edge 184 and the distal edge 183 ofthe integrated fin tab 180 extend from, and substantially perpendicularto the first surface 131 of the base portion 158 of the backing layer130. The proximal edge 184 and distal edge 183 of the integrated fin tab180 are parallel with each other. The integrated fin tab 180 ispositioned so that its distal edge 183 is substantially flush with thedistal end 138 of the base portion 158 of the backing layer 130.

The backing layer 130 is composed of polyurethane. In an alternativeembodiment, the backing layer 130 is composed of silicone. In anotheralternative embodiment, the backing layer 130 is composed of anypolymeric material.

The molded cover 220 envelops and holds together the components of thelead electrode assembly 100. The molded cover 220 also provides rigidityto the lead electrode assembly 100. The molded cover 220 envelops thelead fastener 146 and the backing layer 130. The fin 120 is formed whenthe molded cover 220 covers the fin tab 180. The thickness of theresulting fin 120 is approximately two mm. In alternate embodiments, thethickness of the fin 120 is between approximately one mm andapproximately three mm.

The appendage height of the fin 120 in this embodiment is approximatelyfive mm. In alternative embodiments, the appendage heights range betweenapproximately one mm and approximately ten mm. The appendage length ofthe fin 120 in this embodiment is approximately one cm. In alternativeembodiments, appendage lengths range between approximately two mm andapproximately six cm. In one embodiment, the appendage length of the fin120 is such that the fin is as long as the backing layer 130. In oneembodiment, the appendage length of the fin 120 is such that the fin isas long as the electrode 107. In one embodiment, the appendage length ofthe fin 120 is such that the fin is as long as the molded cover 220.

The molded cover 220 also partially covers the bottom surface 115 of theelectrode 107. In this way, the molded cover 220 attaches the backinglayer 130 to the electrode 107. The molded cover 220 in this embodimentis made of silicone. In an alternate embodiment, the molded cover 220 ismade of any polymeric material. Stitching 360 holds the molded cover220, the electrode 107 and the backing layer 130 together. In oneembodiment, the fin 120 is reinforced with a layer of Dacron® polymermesh positioned between the molded cover 220 and the integrated fin tab180. In another embodiment, the Dacron® polymer mesh is attached only tothe molded cover 220. In other embodiments, the fin 120 is similarlyreinforced with a layer of any polymeric material.

As shown in FIG. 22( b), the fin 120 of the embodiment illustrated inFIG. 22( a) can alternately have a sloped shape. The sloped shape canreduce the resistance offered by the tissue of the patient as it slidesagainst the fin 120 during the insertion of the lead electrode assembly100 into the patient. The slope-shaped fin 120 is constructed so thatthe proximal edge 184 and distal edge 183 of the integrated fin tab 180are not parallel with each other. Instead, distal edge 183 of theintegrated fin tab 180 can be curved so that the distal edge 183 of theintegrated fin tab 180 is closer to the proximal edge 184 at the top 185of the integrated fin tab 180, than at the bottom 186 of the integratedfin tab 180. In alternate embodiments, the distal edge 183 of theintegrated fin tab 180 is not curved. Instead, the distal edge 183 ofthe integrated fin tab 180 is straight, and forms an acute angle withthe first surface 131 of the backing layer 130. In one alternateembodiment, the distal edge 183 of the integrated fin tab 180 forms a45-degree angle with the first surface 131 of the backing layer 130. Inalternate embodiments, the proximal edge 184 of the integrated fin tab180 is curved. In alternate embodiments, the proximal edge 184 of theintegrated fin tab 180 is straight and shaped so that it forms an acuteangle with the first surface 131 of the backing layer 130.

FIG. 22( c) illustrates a front plan view of the lead electrode assembly100 seen in FIG. 22( a). The base portion 158 of the backing layer 130further comprises a first side 133 and second side 134. The first side133 and second side 134 of the base portion 158 of the backing layer 130are substantially parallel. In an alternate embodiment, the first side133 and second side 134 of the backing layer 130 are not parallel. Thebase portion 158 of the backing layer 130 is sized so that it issubstantially the same size and shape as the main body 217 of theelectrode 107.

The integrated fin tab 180 of the backing layer 130 is planar,comprising a first face 181 and a second face 182. The first face 181and second face 182 of the fin tab 180 are substantially parallel witheach other and with the first side 133 and second side 134 of thebacking layer 130. The first face 181 and second face 182 of the fin tab180 extend from, and substantially perpendicular to the first surface131 of the backing layer 130. In another embodiment, the first face 181and second face 182 of the fin tab 180 extend from the first surface 131of the backing layer 130 at angles other than a right angle.

In an alternate embodiment, the first face 181 and a second face 182 ofthe integrated fin tab 180 of the backing layer 130 are notsubstantially parallel to each other. Instead, they are angled, suchthat they are closer together at the top 185 than they are at the bottom186 of the integrated fin tab 180. This shape can reduce the resistanceoffered by the tissue of the patient as it slides against the fin 120during the insertion of the lead electrode assembly 100 into thepatient. In another embodiment, the first face 181 and a second face 182of the integrated fin tab 180 of the backing layer 130 are angled, suchthat they are further apart at the top 185 than they are at the bottom186 of the integrated fin tab 180. This shape can make the fin 120easier to grip with a tool, such as a hemostat.

The fin tab 180 extends from the backing layer 130 at a positioncentered between the first side 133 and the second side 134 of thebacking layer 130. In an alternate embodiment, the fin tab 180 is notcentered between the first side 133 and the second side 134 of thebacking layer 130. An eyelet 301 is formed in the fin 120 of thisembodiment. The eyelet 301 can be used to facilitate the capture of thelead electrode assembly by a tool. The eyelet 301 is formed as a hole225 through the molded cover 220 and between the faces 181 and 182 offin tab 180. In an alternate embodiment, no eyelet is formed in the fin120.

The bottom surface 115 of the electrode 107 comprises a periphery 213and a center 211. The molded cover 220 forms a skirt 222 around theperiphery 213 of the bottom surface 115 of the electrode 107. The skirt222 of the molded cover 220 covers the periphery 213 of the bottomsurface 115 of the electrode 107.

The skirt 222 of the molded cover 220 can act to focuscardioversion/defibrillation energy emitted from the electrode 107 ofthe lead electrode assembly 100 toward the heart of the patient. Becausethe thorax of a patient is surrounded by a layer of fat that is somewhatconductive, the cardioversion/defibrillation energy may tend to arcthrough this layer to reach the active surface 15 of the canister 11(seen in FIG. 1) without passing through the patient's heart. The skirt222 of the lead electrode assembly 100 acts to minimize the loss ofcardioversion/defibrillation energy to surrounding body tissues, or frombeing diverted away from the patient's heart.

The center 211 of the bottom surface 115 of the electrode 107 is notcovered by the molded cover 220 and is left exposed. The width of theperiphery 213 of the bottom surface 115 of the electrode 107 covered bythe molded cover 220 is approximately 0.125 cm.

The area of the exposed center 211 of the bottom surface 115 of theelectrode 107 is approximately five hundred square mm. In alternativeembodiments, the length of the first pair of sides 108 and the secondpair of sides 109 of the electrode 107 vary, such that the area of thecenter 211 of the bottom surface 115 of the electrode has a surface areabetween approximately one hundred sq. mm. and approximately two thousandsq. mm.

FIG. 22( d) illustrates an exploded top view of the lead fastener 146 ofthe embodiments illustrated in FIGS. 22( a)-22(c). The lead fastenerconnects the distal end 102 of the lead 21 and the proximal end 103 ofthe electrode 107. In this embodiment, the lead fastener 146 comprises afirst crimping tube 200, a crimping pin 202 and a second crimping tube201. The crimping pin 202 comprises a first side 203 and a second side204.

The crimping tube 200 crimps the filars 147 of the lead 21 (here, onlyone representative filar 147 is shown) to the first side 203 of crimpingpin 202. The mandrel 219 of the electrode 107 is then wrapped around thesecond side 204 of the crimping pin 202. Crimping tube 201 crimps themandrel 219 to the second side 204 of the crimping pin 202.

The first crimping tube 200, the second crimping tube 201 and thecrimping pin 202 are each made of platinum iridium. In an alternativeembodiment, the first crimping tube 200, the second crimping tube 201and the crimping pin 202 are each made of a metal such as titanium,nickel alloys, stainless steel alloys, platinum, platinum iridium, andmixtures thereof. In other embodiments, the first crimping tube 200, thesecond crimping tube 201 and the crimping pin 202 each comprise anyconductive material.

The electrode 107 in this embodiment comprises a sheet of metallic mesh206 prepared by the process described with reference to FIG. 19( a). Theelectrode 107 has a width measured parallel to the second pair of sides109 of the electrode 107. The width of the mandrel neck 218 of theelectrode 107 is approximately three mm wide. The width of the mandrelof the electrode 107 is approximately five mm wide.

The first pair of sides 108 of the electrode 107 are approximately fivecm in length. The second pair of sides 109 of the electrode 107 areapproximately 1.9 cm in length. In alternative embodiments, the lengthof the first pair of sides 108 and the second pair of sides 109 of theelectrode 107 range independently from approximately one cm toapproximately five cm.

The electrode 107 of this embodiment further comprises four corners 112.The corners 112 of the electrode 107 are rounded. In an alternateembodiment, the corners 112 of the electrode 107 are not rounded.

FIGS. 22( e)-22(g) illustrate the size and position of the fin 120 onthe molded cover of the lead electrode assembly 100.

FIGS. 23( a)-23(c) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiments illustrated in FIGS. 22( a)-22(g). In this embodiment,however, the appendage height of the fin 120 is approximately one cm.The appendage length of the fin 120 in this embodiment is approximately3.5 cm.

As shown in FIG. 23( a), stitching 302 is placed through the moldedcover 220 and the fin 120 to prevent the molded cover 220 from slidingoff the fin tab 180 when the molded cover 220 is subjected to a forcedirected away from the electrode 107.

As shown in FIG. 23( c), the fin 120 (phantom view) extendsapproximately two thirds of the length of the electrode 107.

FIG. 24 illustrates an alternative embodiment of the lead electrodeassembly 100. This embodiment is substantially similar to theembodiments illustrated in FIGS. 22( a)-22(g). In this embodiment,however, the backing layer 130 (not shown) inside the molded cover 220is curved. This results in an electrode 107 that has a curvature ofradius r, such that the bottom surface 115 of the electrode 107 isconcave.

Because a curved electrode 107 may more closely approximate thecurvature of the patient's ribs, this curvature may have the effect ofmaking the lead electrode assembly 100 more comfortable for the patient.In one embodiment, the radius r of the curvature varies throughout theelectrode 107 such that it is intentionally shaped to approximate theshape of the ribs. Lead electrode assemblies 100 can be custommanufactured with an electrode 107 with a curvature r that matches thecurvature of the intended patient's ribcage in the vicinity of theribcage adjacent to which the electrode 107 is to be positioned.

In an alternative embodiment, lead electrode assemblies 100 aremanufactured with an electrode 107 with a radius r that matches thecurvature of the ribcage of a statistically significant number ofpeople.

In another embodiment, lead electrode assemblies 100 with electrodes 107of varying curvatures can be manufactured to allow an electrode radius rto be selected for implantation based on the size of the patient.Smaller radii can be used for children and for smaller adult patients.Larger radii can be used for larger patients. The radius r of thecurvature can range from approximately 5 cm to approximately 35 cmdepending on the size of the patient.

In an alternative embodiment, the electrode 107 of the lead electrodeassembly 100 is flexible, such that it can be bent to conform to thecurvature of the intended patient's rib cage at the time ofimplantation.

FIGS. 25( a)-25(c) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiments illustrated in FIGS. 22( a)-22(g). In this embodiment,however, the backing layer 130 lacks an integrated fin tab 180 mountedon the first surface 131 of the backing layer 130. Moreover, thisembodiment further comprises a backing layer 400 having a fin tab 405.

FIGS. 25( a) and 25(b) illustrate only the backing layer 400, the fintab 405 and the electrode 107 of this embodiment as they are positionedrelative to each other in the complete embodiment. Other components ofthe embodiment are not shown. FIG. 25( c) shows the embodiment in acomplete form.

FIG. 25( a) illustrates a top plan view of the backing layer 400 and theelectrode 107. The backing layer 400 is positioned over the electrode107. The electrode 107 of this embodiment is substantially similar tothe electrode 107 of the embodiment illustrated in FIG. 22( d). In thecomplete embodiment, the mandrel 219 of the electrode 107 is joined tothe lead 21 (not shown) by a lead fastener 146 (not shown) as shown inFIG. 22( a).

The backing layer 400 is a flat, planar member comprising a proximal end137 and a distal end 138. The backing layer 400 further comprises afirst side 133, a second side 134, a first surface 131, and a secondsurface 132 (not shown). The backing layer 400 further comprises awidth, W, measured as the distance between the first side 133 and thesecond side 134.

The backing layer 400 includes a fin tab 405 that is formed from thesame piece of material as the backing layer 400. The first side 133 ofthe backing layer 400 lies over one of the first pair of sides 108 ofthe electrode 107 except over a fin tab region 407. In the fin tabregion 407, the backing layer 400 is wider than the electrode 107. Inthe fin tab region 407, the first side 133 forms a fin tab 405 thatprotrudes from part of the first side 133 of the backing layer 400outside the fin tab region 407. The fin tab 405 extends from the firstside 133 of the backing layer 400 in an orientation substantiallyparallel to the top surface 110 of the electrode 107, beyond the firstside 108 (phantom view) of the electrode 107.

The fin tab 405 comprises a first face 410 and a second face 411 (notshown). The first face 410 of the fin tab 405 is an extension of thefirst surface 131 of the backing layer 400. The second face 411 of thefin tab 405 is an extension of the second surface 132 of the backinglayer 400. Aside from the fin tab 405, the backing layer 405 is formedso that it is of substantially the same size and shape as the main body217 of the electrode 107. The backing layer 400, including the fin tab405, is composed of polyurethane. In an alternate embodiment the backinglayer 400 and fin tab 405 are composed of any polymeric material.

FIG. 25( b) is a side plan view of the backing layer 400 and theelectrode 107. The backing layer 400 is positioned over the electrode107 such that the second surface 132 of the backing layer 400 is placedadjacent to the top surface 110 of the electrode 107. FIG. 25( c)illustrates a bottom plan view of the complete embodiment, in which thebacking layer 400 (not shown), the lead fastener 146 (not shown) and thefin tab 405 (phantom view) are coated with a molded cover 220. When themolded cover 220 is applied over the backing layer 400, a fin 424 isformed over the fin tab 405 (phantom view). The fin 424 comprises aproximal end 403 and a distal end 404.

In one embodiment, the fin 424 is reinforced with a layer of Dacron®polymer mesh positioned between the molded cover 220 and the fin tab405. In another embodiment, the Dacron® polymer mesh is attached only tothe molded cover 220. In other embodiments, the fin 424 is similarlyreinforced with a layer of any polymeric material.

The appendage height, h_(Appendage), of the fin 424 of this embodimentis approximately five mm. In alternative embodiments, the appendageheights range between approximately one mm and approximately ten mm. Theappendage length, L_(Appendage), of the fin 424 of this embodiment ismeasured between the proximal end 403 and the distal end 404 of the fin424. L_(Appendage) is measured where the fin 424 joins the rest of thelead electrode assembly 100. In this embodiment, the appendage length isapproximately one cm. In alternative embodiments, the appendage lengthsrange between approximately two mm and approximately six cm. In oneembodiment, the appendage length of the fin 424 is such that the fin 424runs the length of the electrode 107. In one embodiment, the appendagelength of the fin 424 is such that the fin 424 runs the length of thebacking layer 130 (not shown). In one embodiment, the appendage lengthof the fin 424 is such that the fin 424 runs the length of the moldedcover 220.

FIG. 25( d) illustrates a bottom plan view of an alternate embodiment ofthe lead electrode assembly 100. This embodiment is substantiallysimilar to the lead electrode assembly 100 illustrated in FIGS. 25(a)-25(c). In this embodiment, however, distal end 404 of the fin 424 issloped. The slope shape of the fin 424 is formed by the shape of the fintab 405 (phantom view) inside the fin 424. The backing layer 400gradually widens in the fin tab region 407 (not shown) with distancefrom the proximal end 137 (not shown) to the distal end 138 (not shown)of the backing layer 130 (not shown) until the appendage height isreached. The distal end 404 of the fin 424 is straight and forms anacute angle with the first side 133 of the base portion 158 of thebacking layer 130 (not shown). In an alternate embodiment, the distalend 404 of the fin 424 forms a 45-degree angle with the first side 133of the base portion 158 of the backing layer 130 (not shown). In anotherembodiment, the distal end 404 of the fin 424 is curved slope.

In alternate embodiments, the proximal end 403 of the fin 424 isstraight and shaped so that it forms an acute angle with the first side133 of the base portion 158 of the backing layer 130 (not shown). Inalternate embodiments, the proximal end 403 of the fin 424 is curved.

FIGS. 26( a)-26(c) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 20( a)-20(b). The integrated fin 120 isabsent, however, from the backing layer 130. The lead electrode assembly100 of this embodiment further comprises a cylindrical rod 500 having aloop 515 formed therein. The loop 515 comprises the appendage 118 ofthis embodiment. The loop 515 is a member attached to the electrode 107that can be gripped and used to precisely locate the electrode 107during its surgical implantation within the patient.

FIG. 26( a) illustrates a side plan view of the embodiment. Thecylindrical rod 500 comprises a first straight portion 510, a secondstraight portion 512 and a portion formed into a loop 515. The firststraight portion 510 is separated from the second straight portion 512by the loop 515. The rod 500 is made of platinum iridium. In analternative embodiment, the rod 500 is made of titanium or platinum.

The first straight portion 510 and second straight portion 512 are spotwelded to the top surface 110 of the electrode 107. The loop 515 in therod 500 extends away from the top surface 110 of the electrode 107. Thebacking layer 130 is similar to the backing layer 130 illustrated inFIGS. 20( a)-20(b). The backing layer 130 is disposed over the electrode107. The first straight portion 510 and second straight portion 512 ofthe rod 500 are positioned between the second surface 132 of the backinglayer 130 and the top surface 110 of the electrode 107.

FIG. 26( b) illustrates a cross-sectional rear plan view of theembodiment of the lead electrode assembly shown in FIG. 26( a). Thefirst straight portion 510 and second straight portion 512 arepositioned such that they are parallel to the first pair of sides 108 ofthe electrode 107. The first straight portion 510 and second straightportion 512 are both centered between the first pair of sides 108 of theelectrode 107. In an alternative embodiment, the first straight portion510 and second straight portion 512 are not parallel to and centeredbetween the first pair of sides 108 of the electrode 107.

FIG. 26( c) illustrates a top plan view of the embodiment of the leadelectrode assembly shown in FIG. 26( a). An aperture 517 is formed inthe backing layer 130. The aperture 517 in the backing layer ispositioned such that the loop 515 extends through and beyond theaperture 517 in a direction away from the top surface 110 of theelectrode 107. The backing layer 130 is attached to the electrode 107with stitching 139.

FIGS. 27( a)-27(d) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 20( a)-20(b). This embodiment comprisesa backing layer 610, however, that lacks the integrated fin 120illustrated in FIGS. 20( a)-20(b).

FIG. 27( a) illustrates a top plan view of the backing layer 610 of thisembodiment prior to its attachment to the rest of the lead electrodeassembly 100. The backing layer 610 is cut in a pattern as shown. Thebacking layer comprises a first surface 131, a second surface 132 (notshown), a proximal end 137, a distal end 138, a first side 133, a secondside 134 and an indented fin-forming region 620. The indentedfin-forming region 620 comprises a first edge 690 and a second edge 691.

The backing layer 610 is formed so that the first side 133 and thesecond side 134 are substantially parallel and of substantially the samesize as the first pair of sides 108 of the electrode 107. The distal end138 is formed so that it is substantially perpendicular to the firstside 133 and the second side 134 of the backing layer 610. The distalend 138 is longer than the second pair of sides 109 of the electrode 107by a length A. The backing layer 610 has a varying width C measured fromits proximal end 137 to its distal end 138 along a line parallel to itsfirst side 133.

The backing layer is divided into three sections. A first backingsection 693, a second backing section 692 and an indented fin-formingregion 620 of length A. The length of the fin-forming region 620, A, isapproximately ten mm. In other embodiments, the length of thefin-forming region 620, A, ranges between approximately two mm andapproximately twenty mm. The area within the indented fin-forming region620 is equally divided into a first fin area 612 and a second fin area615. The dividing line 617 between the first fin area 612 and the secondfin area 615 is substantially parallel to the first side 133.

The width, C, of the backing layer 610 is equal to the distance betweenthe second pair of sides 109 of the electrode 107 except in the indentedfin-forming region 620. In the indented fin-forming region 620, thewidth, C, of the backing layer 610 is B. The width, B, of the backinglayer 610 in the fin-forming region 620, is approximately one cm. Inalternate embodiments, the width, B, of the backing layer 610 in thefin-forming region 620 ranges between approximately two mm andapproximately six cm. In other embodiments, however, the fin-formingregion 620 ranges between two mm and the width, C, of the backing layer610. In other embodiments, the fin-forming region 620 is longer than thewidth, C, of the backing layer 610.

The variation in width between the areas inside and outside the indentedfin-forming region 620 forms the first edge 690 and a second edge 691 ofthe fin-forming region 620. A first notch 136(a) is formed on theproximal end 137 the first edge 690 of the fin-forming region 620 of thebacking layer 130. A second notch 136(b) is formed on the proximal end137 the second edge 691 of the fin-forming region 620 of the backinglayer 130. The backing layer 610 in this embodiment is formed offlexible silicone. In alternative embodiments the backing layer 610 isformed of any biocompatible, flexible polymeric material.

FIG. 27( b) illustrates a top plan view of the lead electrode assembly100 of this embodiment. The backing layer 610 is attached to theelectrode 107, so that the first edge 690 and a second edge 691 of thefin-forming region 620 of the backing layer 610 meet. This causes thebacking layer 610 in the first fin area 612 and the second fin area 615to fold together to form a fin 120.

The first notch 136(a) and second notch 136(b) are formed on theproximal end 137 such that, when the first edge 690 and second edge 691of the fin-forming region 620 of the backing layer 130 meet, the firstand second notches 136(a), 136(b) form a notch 136 on the proximal end137 of the backing layer, through which the lead fastener 146 rises.Stitching 660 holds the backing layer to the electrode 107.

FIG. 27( c) illustrates a side plan view of the lead electrode assembly100 of this embodiment. Stitching 660 holds the first fin area 612 (FIG.27( b)) and a second fin area 615 (FIG. 27( b)) of the backing layer 610together to form the fin 120.

FIG. 27( d) illustrates a front plan view of the lead electrode assembly100 of this embodiment. In one embodiment, the fin 120 is reinforcedwith a layer of Dacron® polymer mesh positioned between the first finarea 612 and a second fin area 615. In another embodiment, the Dacron®polymer mesh is attached only to either first fin area 612 or the secondfin area 615. In other embodiments, the fin 120 is similarly reinforcedwith a layer of any polymeric material.

FIGS. 27( e) and 27(f) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 27( a)-27(d). The backing layer 610 issubstantially similar to the backing layer 610 illustrated in FIG. 27(a). The backing layer 610 in this embodiment, however, is cut along line617. The fin 120 of this embodiment comprises a distal edge 129. Thedistal edge 129 of the fin 120 is slope-shaped. The sloped shape canreduce the resistance offered by the tissue of the patient as it slidesagainst the fin 120 during the insertion of the lead electrode assembly100 into the patient.

FIGS. 28( a) and 28(b) illustrate a property of the embodiment of thelead electrode assembly 100 illustrated in FIGS. 27( e) and 27(f). Thebacking layer 610 is flexible, such that the substantially planar fin120 formed therefrom is flexible and able to fold. Because the abilityof the fin 120 to fold effectively reduces its appendage height, it maymake the fin more comfortable to the patient after it is implanted.

FIG. 28( a) shows fin 120 in an upright condition. When pressure isapplied perpendicular to the first surface 131 of backing layer in thefirst fin area 612, along line 677 for example, the fin 120 folds asshown in FIG. 28( b). When the fin 120 folds, its appendage height,H_(Appendage), is reduced. This can be seen by a comparison between FIG.28( a) and FIG. 28( b). The backing layer 610 in this embodiment isformed of a polymeric material. In an alternative embodiment, thebacking layer 610 is formed of any biocompatible, flexible polymericmaterial.

FIGS. 29( a)-29(c) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 27( a)-27(d). As shown in FIG. 29( a),however, the material from the first fin area 612 and the second finarea 615 of the backing layer 610 is not fastened together withstitching 660 in this embodiment. The resulting appendage 118 is formedin the shape of a tube.

In alternate embodiments, the backing layer 610 is coupled to theelectrode 107 such that the material from the first fin area 612 and thesecond fin area 615 of the backing layer 610 does not touch except atthe dividing line 617 between the first fin area 612 and the second finarea 615. The separation between the first fin area 612 and the secondfin area 615 of the backing layer 610 can allow the appendage 118 ofthis embodiment to be highly flexible. This flexibility can reduce theresistance offered by the tissue of the patient as it slides against theappendage 118 during the insertion of the lead electrode assembly 100into the patient.

FIG. 29( b) illustrates a side plan view of the embodiment illustratedin FIG. 29( a). The appendage 118 of this embodiment comprises a distaledge 129. The distal edge 129 of the appendage 118 is slope-shaped. Thesloped shape can reduce the resistance offered by the tissue of thepatient as it slides against the appendage 118 during the insertion ofthe lead electrode assembly 100 into the patient.

In alternate embodiments, the distal edge 129 of the tube formed by theappendage 118 is closed. In one embodiment, the distal edge 129 of theappendage 118 is closed by a cap (not shown). In another embodiment, thedistal edge 129 of the appendage 118 is closed with stitching placedbetween the first fin area 612 and the second fin area 615 only at thedistal edge 129 of the appendage 118. In another embodiment, the distaledge 129 of the appendage 118 is closed by any other means known in theart for this purpose.

FIG. 29( c) illustrates a top plan view of the embodiment illustrated inFIGS. 29( a)-29(b). In particular, the backing layer 610 is shown. Theappendage 118 and its distal edge 129 are also illustrated, showing theopening formed by the distal edge 129 and the tube-shaped appendage 118.

FIGS. 30( a)-30(d) illustrate an alternative embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 20( a)-20(b). The backing layer 130 ofthis embodiment, however, lacks an integrated fin.

FIG. 30( a) illustrates a front plan view of the lead electrodeassembly. The fin 120 in this embodiment comprises a fin head 700 andflexible joining material 702. The fin head 700 comprises a rectangularsheet having a first face 705, a second face 706, a first end 710 and asecond end 712. The fin head 700 further comprises a height measuredalong the first face 705 between the first end 710 and the second end712 and a length measured perpendicular to its height. The fin head 700is made of rigid silicone, which has a high durometer. In alternateembodiments, the fin head 700 is composed of any rigid biocompatiblematerial, such as a rigid biocompatible polymeric material.

The flexible joining material 702 comprises a rectangular sheet having afirst face 720, a second face 721, a first end 718 and a second end 719.The flexible joining material 702 further comprises a height measuredalong the first face between the first end 718 and the second end 719.The flexible joining material 702 also comprises a length measuredperpendicular to its height. The length of the flexible joining material702 is the same as the length of fin head 700.

The second end 712 of the second face 706 of the fin head 700 isattached to the first end 718 of the first face 720 of the flexiblejoining material 702. The fin head 700 is attached to the flexiblejoining material 702 with stitching 725. The second end 719 of the firstface 720 of the flexible joining material 702 is attached to the firstsurface 131 of the backing material 130. The flexible joining material702 is attached to the backing material 130 with stitching 730. Theflexible joining material 702 is made of flexible silicone. It will berecognized by one skilled in the art, however, that the flexible joiningmaterial 702 may be made from many other flexible materials, such as aflexible polymeric material.

FIG. 30( b) illustrates a property of the fin 120. When pressure isapplied perpendicular to the first surface 705 (FIG. 30( a)) of the finhead 205 (FIG. 30( a)), the fin 120 folds as shown. When the fin 120folds, its appendage height, H_(Appendage), is reduced. This can be seenby a comparison between FIG. 30( a), which shows the fin 120 in anupright position and FIG. 30( b) which shows the fin 120 in a foldedposition. FIG. 30( c) illustrates a top planar view of the leadelectrode assembly 100 of the embodiment illustrated in FIGS. 30( a) and30(b). Neither the corners of the electrode 107 nor the corners 735 ofthe backing layer 130 of this embodiment are rounded. In an alternateembodiment, both the corners of the electrode 107 and the corners 735 ofthe backing layer 130 of this embodiment are rounded.

FIG. 31 illustrates an alternative embodiment of the lead electrodeassembly 100. This embodiment is substantially similar to the embodimentillustrated in FIGS. 30( a)-30(d). The backing layer 130 of thisembodiment, however, lacks a fin head and flexible joining material asshown in FIGS. 30( a)-30(d). The appendage 118 in this embodimentcomprises a tube 740 having an interior 755, an exterior 756, a distalend 757 and a proximal end 758. The tube comprises a sheet of material750. The sheet of material 750 is substantially rectangular having afirst pair of sides 751, a second pair of sides 752, a first surface 753and a second surface 754.

The sheet of material 750 is folded so that its first pair of sides 751abut each other. The folded sheet of material 750 forms a tube 740. Thefirst surface 753 of the sheet of material 750 faces the interior 755 ofthe tube 740. The second surface 754 of the sheet of material 750 facesthe exterior of the tube 756. In folding the sheet of material 750 sothat the first pair of sides 751 abut each other, the second pair ofsides 752 of the sheet of material 750 are folded in a circular shape toform the distal end 757 and proximal end 758 of the tube 740. Thisresults in the tube 740 having a cylindrical shape. The diameter of thecircular distal end 757 and proximal end 758 of the tube 756 isapproximately five mm. In alternate embodiments, the diameter rangebetween approximately one mm and approximately ten mm. The length of thetube 756 as measured between the distal end 757 and proximal end 758 ofthe tube 756 is approximately one cm. In alternate embodiments, lengthof the tube 756 ranges between approximately two mm and approximatelysix cm. In one embodiment, the tube 756 is substantially as long as theelectrode 107.

The second surface 754 of the sheet of material 750 is attached to thefirst surface 131 of the backing layer 130. The first pair of sides 751of the sheet of material 750 are attached to the backing layer 130 withstitching 760.

In alternate embodiments, the distal end 757 of the tube 740 is closed.In one embodiment, the distal end 757 of the tube 740 is closed by a cap(not shown). In another embodiment, the distal end 757 of the tube 740is closed by holding one of the second pair of sides 752 of the sheet ofmaterial 750 closed with stitching. In another embodiment, the distalend 757 of the tube 740 is closed by any other means known in the artfor this purpose.

It should be noted that the appendage 118 in some alternativeembodiments comprises a tube with a shape other than a cylinder. Anexample of a tube with a shape other than cylindrical is illustratedbelow in FIG. 32.

FIG. 32 illustrates an alternative embodiment of the lead electrodeassembly 100. The appendage 118 of this embodiment comprises a tube 770having an interior 755 an exterior 756, a distal end 757 and a proximalend 758. The tube comprises a first sheet of material 775, a secondsheet of material 776 and a third sheet of material 777. The first sheetof material 775, the second sheet of material 776 and the third sheet ofmaterial 777 are all substantially rectangular in shape. Each comprisesa first pair of sides 784, a second pair of sides 786, a first surface788 and a second surface 789. The first pair of sides 784 of each sheetof material are parallel to each other. In another embodiment, the firstpair of sides 784 of each sheet of material are non-parallel. The secondpair of sides 786 of each sheet of material are parallel to each other.In another embodiment, the second pair of sides 786 of each sheet ofmaterial are non-parallel.

The first pairs of sides 784 of each sheet of material are attached tothe first pair of sides 784 of the other sheets of material. In this waythe second pair of sides 786 of the first sheet of material 775, thesecond sheet of material 776 and the third sheet of material 777 form atriangular shaped distal end 757 and proximal end 758 of the tube 770.The sheets of material are attached to each other such that the secondsurface 789 of each sheet of material faces the interior 755 of the tube770. The sheets of material are attached to each other with stitching791.

The height of the tube 770 is approximately five mm. In alternateembodiments, the height ranges between approximately one mm andapproximately ten mm. The length of the tube 770 as measured between thedistal end 757 and proximal end 758 of the tube 770 is approximately onecm. In alternate embodiments, length of the tube 770 ranges betweenapproximately two mm and approximately six cm. In one embodiment, thetube 770 is substantially as long as the electrode 107.

The second sheet of material 776 is attached to the backing layer 130with stitching 790. The first surface 788 of the second sheet ofmaterial 776 is positioned next to the first surface 131 of the backinglayer 130.

In alternate embodiments, some or all of the sheets of material arereinforced with a layer of Dacron® polymer mesh. In one embodiment, theDacron® polymer mesh is attached to the first surface 788 of each sheetof material. In another embodiment, the Dacron® polymer mesh is attachedto the second surface 789 of each sheet of material. In anotherembodiment, the sheets of material are similarly reinforced with a layerof any polymeric material.

In alternate embodiments, the distal end 757 of the tube 770 is closed.In one embodiment, the distal end 757 of the tube 770 is closed by acap. In another embodiment, the distal end 757 of the tube 770 is closedby holding the sides 786 of the first sheet of material 775, the secondsheet of material 776 and the third sheet of material 777 that form thedistal end 757 of the tube 770 together with stitching. In anotherembodiment, the distal end 757 of the tube 770 is closed by any othermeans known in the art for this purpose.

FIGS. 33( a)-33(d) illustrate various possible positions for theappendage 118 relative to the lead 21 of the lead electrode assembly100. Additionally, up to this point, all embodiments of the electrode107 illustrated and discussed have had a rectangular shape. Thesefigures illustrate alternative embodiments with electrodes 107 ofdifferent shapes.

At this point, it is useful to set out two definitions in order todiscuss the possible orientation of appendages 118. The interface lineis defined as the center line of the appendage 118 as traced on theelectrode 107. FIG. 33( a) illustrates the interface line 800 of theappendage 118 of a lead electrode assembly 100. The line of the lead isdefined as the line along which the lead 21 of the lead electrodeassembly 100 enters the lead fastener 146. The line of the lead 805 ofline 21 is shown as it enters the lead fastener 146 (in phantom). As thelead 21 approaches the lead fastener 146, the closest section 807 of thelead 21 forms the line of the lead. When the lead 21 is not bent, theentire lead 21 lies along the line of the lead.

FIG. 33( b) illustrates an embodiment wherein the lead 21 is not bentand the entire lead 21 lies along the line of the lead 805. Theelectrode length, L_(Electrode), is the length of the electrode 107 asmeasured along the interface line 800. In the embodiments of the leadelectrode assembly 100 shown in FIGS. 33( b) and 33(c), the interfaceline 800 is the same line as the line of the lead 805. In the embodimentshown in FIG. 33( a) the interface line 800 is parallel with the line ofthe lead 805. In the embodiment of the lead electrode assembly 100 shownin FIG. 33( d), the interface line 800 intersects the lead fastener 146(phantom view).

FIGS. 33( e)-33(h) show various additional electrode shapes disposed invarious lead electrode assemblies 100. The electrode shapes are notlimited, however, to the shapes specifically illustrated. The electrode204 depicted in FIG. 33( e) has a “thumbnail” shape. The distal end 104of this electrode 107 is generally rounded. As the electrode 107 movesdistally along its length, the conductive surface terminates at theproximal end 103 of the electrode 107.

An ellipsoidal shaped electrode 107 is depicted in FIG. 33( f). Thedistal end 104 of the ellipsoidal shaped electrode 107 is generallyrounded. As the ellipsoidal shaped electrode 107 moves distally alongits length, the conductive surface terminates in a rounded proximal end103. A circular shaped electrode 107 is illustrated in FIG. 33( g). Atriangular shaped electrode 107 is depicted in FIG. 33( h). Triangularshaped electrodes 107 also incorporate electrodes that are substantiallytriangular in shape. In particular to FIG. 33( h), the corners of thetriangular shaped electrode 107 are rounded.

Several lead electrode assembly manipulation tools 927 have beendeveloped to manipulate the lead electrode assemblies during theirsurgical implantation. FIG. 34 illustrates an embodiment of a leadelectrode assembly manipulation tool 927. The lead electrode assemblymanipulation tool 927 comprises an enhanced hemostat 930 used tomanipulate lead electrode assemblies 100 comprising an eyelet duringtheir implantation in patients.

The enhanced hemostat 930 comprises the following components: a hemostathaving a first prong 931, a second prong 932, a hinge 939 and an eyeletpin 940. The first prong 931 is attached to the second prong 932 by thehinge 939. The eyelet pin is attached to the second prong 932.

The first prong 931 comprises a first end 933 and a second end 934. Thesecond prong 932 comprises a first end 935 and a second end 936. Thefirst prong and second prong are approximately seventy-five cm long andcurved with a radius of approximately thirty cm. In alternateembodiments, the curvature of the hemostat does not have a radius ofapproximately thirty cm, but instead approximates the curvature of thethorax of a patient. In one embodiment, the curvature of the hemostatapproximates the curvature of the thorax of a patient along asubcutaneous path taken from the anterior axillary line, posteriorlytoward the spine.

The first prong 931 is pivotally attached to the second prong 932 by thehinge 939. The hinge is attached to the first prong 931 approximatelyten cm from the first end 933. In this embodiment, the hinge is attachedto the second prong 932 approximately ten cm from the second end 935.

The eyelet pin 940 can be inserted through the eyelet 301 of a fin 120of the lead electrode assembly 100 such as the lead electrode assembly100 discussed with reference to FIG. 22( a)-22(g) as a means ofcapturing the lead electrode assembly 100 prior to its implantation in apatient.

The eyelet pin 940 is a cylindrical member having a first end 941 and asecond end 942. In an alternate embodiment, the eyelet pin 940 is ahook-shaped member. The diameter of the cylinder is approximately twomm. In alternate embodiments, the diameter of the cylinder ranges fromapproximately one mm to approximately five mm. The length of the eyeletpin 940 is approximately eight mm. In alternate embodiments, the lengthof the eyelet pin 940 ranges from approximately four to approximatelyfifteen mm.

The first end of the eyelet pin 940 is attached to the second prong 932,approximately 8 mm from the second end 936 of the second prong 932. Inalternate embodiments, the eyelet pin 940 is attached to the secondprong 932 at various lengths from the second end 936 of the second prong932. The eyelet pin 940 is attached to the second prong 932 in anorientation perpendicular to the length of the second prong 932. Theeyelet pin 940 is attached to the second prong 932 so that it extendsaway from the second end 934 of the first prong 931.

In this embodiment, all of the components are made of stainless steel.In an alternative embodiment, some or all of the components are composedmetals other than stainless steel or are composed of a polymericmaterial.

We now turn to a discussion of the positions of the components thatcomprise an entire S-ICD system including the lead electrode assembly100 when it is implanted in a patient. FIGS. 35( a) and 35(b) illustratean embodiment of the S-ICD system implanted in a patient as a means ofproviding cardioversion/defibrillation energy.

FIG. 35( a) is a perspective view of a patient's ribcage with animplanted S-ICD system. The S-ICD canister 11 is implantedsubcutaneously in the anterior thorax outside the ribcage 1031 of thepatient, left of the sternum 920 in the area over the fifth rib 1038 andsixth rib 1036. The S-ICD canister 11, however, may alternately beimplanted anywhere over the area between the third rib and the twelfthrib. The lead 21 of the lead electrode assembly 100 is physicallyconnected to the S-ICD canister 11 where the transthoracic cardiacpacing energy or effective cardioversion/defibrillation shock energy(effective energy) is generated. The term “effective energy” as used inthis specification can encompass various terms such as field strength,current density and voltage gradient.

The lead 21 of the lead electrode assembly 100 travels from the S-ICDcanister 11 to the electrode 107, which is implanted subcutaneously inthe posterior thorax outside the ribcage 1031 of the patient in the areaover the eighth rib 1030 and ninth rib 1034. The electrode 107, mayalternately be implanted subcutaneously anywhere in the posterior thoraxoutside the ribcage 1031 of the patient in the area over the third rib1030 and the twelfth rib 1034. The bottom surface 115 of the electrode107 faces the ribcage. The electrode or active surface 15 (phantom view)of the canister 11 also faces the ribcage.

FIG. 35( b) is a cross-sectional side plan view of the patient's ribcage. Here it is seen that the lead 21 travels around the circumferenceof the thorax, in the subcutaneous layer beneath the fat 1050 betweenthe outside of the ribcage 1031 and the skin 1055 covering the thorax.

We now turn to a discussion of a method by which the lead electrodeassembly 100 of the S-ICD system is implanted in a patient using astandard hemostat as well as the enhanced hemostat described above. FIG.36 and FIGS. 37( a)-37(d) illustrate aspects of this method. Inoperation, as seen in FIG. 36, an incision 905 is made in the patient900 in the anterior thorax between the patient's third and fifth rib,left of the sternum 920. The incision can alternately be made in anylocation between the patient's third and twelfth rib. The incision canbe made vertically (as shown), horizontally or angulated. In order tominimize scarring, the incision can be made along Langher's lines.

FIG. 37( a) shows a bottom view cross-section of the patient 900, alongthe line 37(a) shown in FIG. 36. A hemostat 930, with prongs 932 isintroduced into the incision 905. The hemostat 930 is inserted with itsprongs together without anything gripped between them. The prongs 932 ofthe hemostat 930 are pushed through the fat 1050 between the skin 1055of the thorax and the ribcage 1031 to create a subcutaneous path 1090.The prongs 932 of the hemostat 930 can alternately be pushed beneath thefat 1050 that lies between the skin 1055 of the thorax and the ribcage1031 to create a subcutaneous path 1090 between the fat 1050 and theribcage 1031.

The hemostat is moved around the ribcage 1031 until the subcutaneouspath 1090 reaches within approximately 10 cm of the spine 1035 betweenthe eighth rib 1030 and ninth rib 1034 (this location is best seen inFIG. 35( a)) between the skin 1055 and the ribcage 1031. Thesubcutaneous path 1090 can alternately be made to reach any locationbetween the skin 1055 and the ribcage 1031 between the patient's thirdand twelfth rib. The hemostat 930 is then withdrawn. Alternately, thehemostat 930 can be moved around the ribcage 1031 until the subcutaneouspath 1090 terminates at a termination point 1085 at which a line 1084drawn from the termination point 1085 to the incision 905 wouldintersect the heart 910.

Next, as shown in FIG. 37( b), the appendage 118 of a lead electrodeassembly 100 is squeezed between the tongs 932 of a hemostat 930. Asshown in FIG. 37( c), the lead electrode assembly 100 and hemostat tongs932 are introduced to the subcutaneous path 1090 and pushed through thesubcutaneous path until the lead electrode assembly 100 reaches thetermination point 1085 of the path. The appendage 118 of the leadelectrode assembly 100 is then released from the tongs 932 of thehemostat 930. The hemostat 930 is then withdrawn from the subcutaneouspath 1090.

In an alternative method, the enhanced hemostat 930 seen in FIG. 34 isused to introduce the lead electrode assembly 100 into the subcutaneouspath 1090 created as discussed above. After the subcutaneous path 1090is created, the lead electrode assembly 100 is attached to the enhancedhemostat 930 as shown in FIG. 37( d). Eyelet pin 1108 is insertedthrough the eyelet 301 in the fin 120 of the lead electrode assembly100. The enhanced hemostat 930 is then used to introduce the leadelectrode assembly 100 into the subcutaneous path 1090, as shown in FIG.37( c). The lead electrode assembly 100 is then moved through thesubcutaneous path 1090 until the electrode 107 reaches the end of thepath 1085. The enhanced hemostat 930 is then moved until the leadelectrode assembly 100 is released from the eyelet pin 940. The enhancedhemostat 930 is then withdrawn from the subcutaneous path 1090.

FIGS. 38( a)-38(c) illustrate an alternative embodiment of the leadelectrode assembly 100. The appendage 118 of the lead electrode assembly100 of this embodiment comprises a rail 1100. FIG. 38( a) illustratesthe rail 1100 of the lead electrode assembly 100 of this embodiment. Therail 1100 is a member attached to the electrode 107 that can be capturedby a lead electrode assembly manipulation tool and used to preciselylocate the electrode 107 during its surgical implantation within thepatient. The rail 1100 comprises three sections: a foundation 1105, ariser 1110 and a head 1115. The foundation 1105 is separated from thehead 1115 by the riser 1125.

The foundation 1105 comprises a flat, substantially planar member,comprising a first pair of sides 1106 and a second pair of sides 1107.The first pair of sides 1106 of the foundation 1105 are substantiallylinear and substantially parallel. In an alternate embodiment, the firstpair of sides 1106 of the foundation 1105 are neither linear norparallel. The length of the first pair of sides 1106 of the foundation1105 is approximately two cm. In alternate embodiments, the length ofthe first pair of sides 1106 of the foundation 1105 ranges fromapproximately two mm to approximately six cm. In an alternateembodiment, the first pair of sides 1106 of the foundation 1105 are aslong as the electrode 107 (not shown) of the lead electrode assembly 100(not shown).

The second pair of sides 1107 of the foundation 1105 are substantiallylinear and substantially parallel. In an alternate embodiment, thesecond pair of sides 1107 of the foundation 1105 are neither linear norparallel. The length of the second pair of sides 1107 of the foundation1105 is approximately one cm. In alternate embodiments, the length ofthe second pair of sides 1107 of the foundation 1105 ranges fromapproximately five mm to approximately three cm.

The foundation 1105 further comprises a top surface 1120 and a bottomsurface 1121. The foundation 1105 has a thickness, measured as thedistance between the top surface 1120 and the bottom surface 1121. Thethickness of the foundation 1105 is two mm. In alternate embodiments,the thickness of the foundation 1105 ranges between approximately one mmand approximately five mm.

Turning now to the riser 1110, the riser 1110 comprises a flat,substantially planar protrusion from the top surface 1120 of thefoundation 1105 of the rail 1100. The riser comprises a first face 1125,a second face 1126, a top 1127, a bottom 1128, a proximal end 1124 and adistal end 1123. The first face 1125 and second face 1126 are parallelto each other and perpendicular to the top surface 1120 of thefoundation 1105. The first face 1125 and a second face 1126 of the riser1110 are parallel to the first pair of sides 1106 of the foundation1105. The bottom 1128 of the riser 1110 joins the foundation 1105 in aposition centered between the first pair of sides 1106 of the foundation1105. The distal end 1123 of the riser 1110 and the proximal end 1124 ofthe riser 1110 are parallel to each other and perpendicular to the topsurface 1120 of the foundation 1105. In other embodiments, the distalend 1123 of the riser 1110 and the proximal end 1124 of the riser 1110are not parallel to each other.

In one embodiment, the distal end 1123 of the riser 1110 is notperpendicular the top surface 1120 of the foundation 1105. Instead, thedistal end 1123 of the riser 1110 is sloped, so that the distal end 1123and the proximal end 1124 of the riser 1110 are closer at the top 1127of the riser 1110 than at the bottom 1128 of the riser. A slanted distalend 1123 makes the rail 1100 of the lead electrode assembly 100 offerless resistance against the tissues of the patient during insertion intothe patient.

The height of the riser, H_(Riser), is measured as the distance betweenthe top surface 1120 of the foundation 1105 to the head 1115,perpendicular to the top surface 1120 of the foundation 1105. The heightof the riser is approximately five mm. In alternate embodiments, theheight of the riser ranges from approximately one mm to approximatelyten mm.

The riser 1110 has a width, measured as the distance between the firstface 1125 and the second face 1126. The width of the riser 1110 is twomm. In alternate embodiments, the width of the riser 1110 ranges fromapproximately one mm to approximately six mm.

Turning now to the head 1115, the head 1115 is a flat, substantiallyplanar member. The head 1115 comprises a first pair of sides 1136, asecond pair of sides 1137, a top surface 1116 and a bottom surface 1117(not shown). The first pair of sides 1136 and the second pair of sides1137 of the head 1115 are substantially linear and substantiallyparallel. In an alternate embodiment, the first pair of sides 1136 ofthe head 1115 are neither linear nor parallel. In an alternateembodiment, the second pair of sides 1137 of the head 1115 are neitherlinear nor parallel.

The length of the first pair of sides 1136 of the head 1115 is equal tothe length of the first pair of sides 1106 of the foundation 1105. Inalternate embodiments, the length of the first pair of sides 1136 of thehead 1115 is unequal to the length of the first pair of sides 1106 ofthe foundation 1105. The length of the second pair of sides 1137 of thehead 1115 is approximately five mm. In alternate embodiments, the lengthof the second pair of sides 1137 of the head 1115 ranges fromapproximately three mm to approximately ten mm.

The bottom surface 1117 of the head 1115 joins the top 1127 of the riser1110 opposite the foundation 1105 of the rail 1100. The top surface 1116and the bottom surface 1117 of the head 1115 are parallel to the topsurface 1120 of the foundation 1105. In an alternate embodiment, the topsurface 1116 and the bottom surface 1117 of the head 1115 are notparallel to the top surface 1120 of the foundation 1105.

The head 1115 has a thickness, measured as the distance between the topsurface 1116 and the bottom surface 1117 of the head 1115. The thicknessof the head 1115 is approximately two mm. In alternate embodiments, thethickness of the head ranges between approximately two mm andapproximately ten mm.

The foundation 1105, the head 1115 and the riser 1110 are made ofstainless steel. In alternate embodiments, some or all of the sectionsof the rail 1100 are made of metals other than stainless steel. Inalternate embodiments, some or all of the sections of the rail 1100 aremade of a polymeric material such as a polyurethane, a polyamide, apolyetheretherketone (PEEK), a polyether block amide (PEBA), apolytetrafluoroethylene (PTFE), a silicone and mixtures thereof.

The foundation 1105, the head 1115 and the riser 1110 are machined fromthe same piece of material. In an alternate embodiment, some or all ofthe sections are formed independently and welded to the others.

Turning in detail to FIG. 38( b), the position of the rail 1100 withinthe lead electrode assembly 100 will be discussed. The rail 1100 ispositioned so that its bottom surface 1121 is adjacent to and covers aregion of the first surface 131 of the backing layer 130. The rail iscentered between the first side 133 and second side 134 of the backinglayer 130. In an alternate embodiment, the rail is not centered betweenthe first side 133 and second side 134 of the backing layer 130. In analternate embodiment, there is no backing layer 130 and the rail 1100 ispositioned so that its bottom surface 1121 is adjacent to the topsurface 110 of the electrode 107.

Turning now to the electrode 107 of this embodiment, the electrode 107is the same shape and size as the electrode 107 discussed with referenceto FIGS. 22( a)-(g). In alternative embodiments, the length of the firstpair of sides 108 (not shown) and second pair of sides 109 (not shown)of the electrode 107 range independently between approximately one cmand approximately five cm.

Turning now to the molded cover 220, the skirt 222 of the molded cover220 partially covers the bottom surface 115 of the electrode 107 asdiscussed with reference to FIG. 22( d). The molded cover 220 furthersubstantially covers the first surface 131 of the backing layer 130. Themolded cover 220 does not cover the first surface 131 of the backinglayer 220 in the region in which the bottom surface 1121 of the rail1100 is adjacent to the backing layer 130. Instead, the molded cover 220in this region substantially covers the top surface 1120 of the rail1100. The molded cover 220 abuts the first face 1125 and second face1126 of the riser 1110 of the rail 1100.

Turning to FIG. 38( c), the position of the lead 21 and the appendage118 will now be discussed. The interface line 800 of the appendage 118and the line of the lead 805 are the same line. In an alternateembodiment, interface line 800 of the appendage 118 and the line of thelead 805 are not the same line. The line of the lead 805 is centeredbetween the first pair of sides 108 (phantom view) of the electrode 107(phantom view). In an alternate embodiment, the line of the lead 805 isnot centered between the first pair of sides 108 of the electrode 107.

FIG. 39 illustrates an alternative embodiment of the lead electrodeassembly 100. This embodiment is substantially similar to the embodimentillustrated in FIGS. 38( a)-38(c). In this embodiment, however, thedimensions of the electrode 107 are different from those of theembodiment illustrated in FIGS. 38( a)-38(c). The first pair of sides108 of the electrode 107 (phantom view) are approximately twenty-four mmin length. The second pair of sides 109 of the electrode 107 areapproximately four cm in length. In alternative embodiments, the lengthof the first pair of sides 108 and second pair of sides 109 of theelectrode 107 range independently between approximately one cm andapproximately five cm.

The interface line 800 of the rail 1100 is parallel to the line of thelead 805. In an alternate embodiment, the interface line 800 of the rail1110 is not parallel to the line of the lead 805. The interface line 800of the rail 1100 is centered between the first pair of sides 108 of theelectrode 107. In an alternate embodiment, the interface line 800 of therail 1100 is not centered between the first pair of sides 108 of theelectrode 107. The line of the lead 805 is not centered between thefirst pair of sides 108 of the electrode 107. Because the lead 805 isnot centered between the first pair of sides 108 of the electrode 107,the lead rail 1110 may be more easily accessed by a lead electrodemanipulation tool (not shown). In an alternate embodiment, the line ofthe lead 805 is centered between the first pair of sides 108 of theelectrode 107.

FIG. 40 illustrates a lead electrode assembly manipulation tool 927useful for manipulating a lead electrode assembly (not shown) having anappendage 118 comprising a rail 1100 during the implantation of the leadelectrode assembly 100 in a patient. Examples of such lead electrodeassembly 100 embodiments are shown in FIGS. 38( a)-38(c) and 39.

The lead electrode assembly manipulation tool 927 comprises a handle1142, a rod 1144 and a rail fork 1146. The handle 1142 is connected tothe rod 1144. The rail fork 1146 is also connected to the rod 1144. Therod 1144 is a cylindrical member with a diameter of approximately fourmm, approximately twenty-five cm in length, having a proximal end 1147and a distal end 1148. The rod 1144 is curved with a radius ofapproximately twenty cm. The rod 1144 is made of steel. In otherembodiments, the rod 1144 is composed of titanium, a polymeric materialor any other material suitable for this purpose.

The handle 1142 is a cylindrical member with a diameter sized to fitcomfortably in the palm of a surgeon's hand. The rod is connected to theproximal end 1147 of the rod 1144. In an alternate embodiment, thehandle 1142 is not cylindrical. In an alternate embodiment, the handle1142 has ergonomic contours. The handle is made of polyurethane. In analternate embodiment, the handle is made of any metal, or any polymericmaterial suitable for this purpose.

Turning now to FIG. 40( b), the rail fork 1146 is attached to the distalend 1148 of the rod 1144. The rod 1144 further comprises a slot 1162(FIG. 40( c)) in its distal end 1148. The rail fork 1146 comprises apair of tines 1151 separated by a gap 1153 and a tine base 1160 having atang 1161.

Each of the pair of tines 1151 has a proximal end 1154 and a distal end1155. The proximal ends 1154 of the pair of tines 1151 are attached tothe tine base 1160. Each of the pair of tines 1151 has a substantiallyrectangular form with straight inner sides 1156 and straight outer sides1157. The distal ends 1155 of each of the pair of tines 1151 arerounded. Referring simultaneously to FIGS. 40( b) and 38(a), the lengthof the pair of tines 1151, measured from the distal end 1155 to theproximal end 1154, is substantially equal to the length of the firstpair of sides 1106 of the rail 1100 of the lead electrode assembly 100.In alternate embodiments, the length of the pair of tines 1151 issubstantially greater than or less than the length of the first pair ofsides 1106 of the rail 1100.

The pair of tines 1151 are separated by a gap 1153 formed by the innersides 1156 of the pair of tines 1151 and the tine base 1160. The pair oftines 1151 and the tine base 1160 comprising the rail fork 1146 arepunched from a single sheet of steel having a thickness of approximatelythree mm. In other embodiments, the rail fork 1146 is composed oftitanium, a polymeric material or any other material suitable for thispurpose. In one embodiment, the handle 1142, the rod 1144 and the railfork 1146 are all made from the same piece of material.

FIG. 40( c) illustrates a side plan view of the lead electrode assemblymanipulation tool 927. The rod 1144 further comprises a slot 1162 in itsdistal end 1148. The tine base 1160 connects the pair of tines 1151 tothe distal end 1148 of the rod 1144. The tine base 1160 comprises a tang1161 (phantom view). The tang 1161 is inserted in the slot 1162 in therod 1144. The tang 1161 is welded in the slot 1162 of the rod 1144.

We now turn to a description of the use of the lead electrode assemblymanipulation tool 927 in the implantation of a lead electrode assembly100 into a patient. As discussed with reference to FIG. 36, an incision905 is made in the patient 900. As discussed with reference to FIG. 37(a), a subcutaneous path 1090 is created in the patent 900 with ahemostat 932.

As shown in FIG. 40( d), the lead electrode assembly 100 is thencaptured by the lead electrode assembly manipulation tool 927. The rail1100 of the lead electrode assembly 100 is inserted into the rail fork1146 of the lead electrode assembly manipulation tool 927. The riser1110 (phantom view) of the rail 1100 is placed into the gap 1153 betweenthe pair of tines 1151 of the rail fork 1146. The pair of tines 1151 fitbetween the bottom surface 1117 (FIG. 38( a)) of the head 1115 (FIG. 38(a)) of the rail 1100 and the molded cover 220 (FIG. 38( a)). The rail1100 is slid toward the proximal end 1155 of the pair of tines 1151until the riser 1110 of the rail 1100 reaches the tine base 1160 of therail fork 1146. The lead 21 of the lead electrode assembly 100 can thenbe pulled in toward the handle 1142 of the lead electrode assemblymanipulation tool 927 until it is taut. This acts to prevent the rail1100 of the lead electrode assembly 100 from sliding toward the distalend 1151 of the pair of tines 1151 of the rail fork 1146.

As discussed with reference to FIG. 37( c), the lead electrode assemblymanipulation tool 927 may then be used to place the lead electrodeassembly 100 into the incision 905 of the patient 900 and used to movethe electrode 107 to the termination point 1085 of the subcutaneous path1090. The lead electrode assembly 100 is then released from the leadelectrode assembly manipulation tool 927. To achieve this, the lead 21of the lead electrode assembly 100 is released so that the pair of tines1151 of the rail fork 1146 of the lead electrode assembly manipulationtool 927 can slide relative to the rail 1100 of the lead electrodeassembly 100. The lead electrode assembly manipulation tool 927 may thenbe extracted from the subcutaneous path 1090, leaving the lead electrodeassembly 100 behind.

FIGS. 41( a)-41(b) illustrate an alternative embodiment of the leadelectrode assembly 100. The backing layer 130 of this embodiment lacksan integrated fin tab 180 (e.g. fin tab 180 in FIG. 22( a)-22(b)). Thelead electrode assembly 100 of this embodiment further comprises apocket 1300.

FIG. 41( a) illustrates a cross-sectional side plan view of thisembodiment. The pocket 1300 comprises a layer of material 1315 andstitching 360. The pocket further comprises an interior 1305 and anopening 1310. The layer of material 1315 is attached to the molded cover220 with the stitching 360. The molded cover 220 is, in turn, attachedto the electrode 107.

The molded cover 220 comprises an outer surface 1330 and a top surface1331. The outer surface 1330 of the molded cover 220 is the surface ofthe molded cover 220 that does not lie adjacent to the backing layer 131or the electrode 107. The top surface 1331 of the molded cover 220 facesaway from, and parallel to the electrode 107. The layer of material 1315of the pocket 1300 comprises an inner face 1316 and an outer face 1317.The layer of material 1315 is attached to the top surface 1331 of themolded cover 220 so that the inner face 1316 of the layer of material1315 faces the top surface 1331 of the molded cover 220. The inner face1316 of the layer of material 1315 also faces the top surface 110 of theelectrode 107.

The layer of material 1315 is made of polyurethane. In otherembodiments, the layer of material 1315 is made of any biocompatiblematerial suitable for this purpose. In other embodiments, the layer ofmaterial 1315 is made of any biocompatible polymeric material. Thestitching 360 fastening the layer of material 1315 to the top surface1331 of the molded cover 220 is comprised of nylon. In alternateembodiments, the stitching 360 comprises any polymeric material.

FIG. 41( b) illustrates a top plan view of the lead electrode assembly100 of FIG. 41( a). The top surface 1331 of the molded cover 220 has afirst side 1333, a second side 1334, a proximal end 1336, a distal end1337, a length and a width.

The proximal end 1336, distal end 1337, first side 1333 and second side1334 of the top surface 1331 of the molded cover 220 are positionedsubstantially over the proximal end 137 (phantom view), distal end 138(phantom view), first side 133 (not shown) and second side 134 (notshown) of the backing layer 130 (phantom view) respectively.

The width of the top surface 1331 of the molded cover 220 is measured asthe distance between the first side 1333 and second side 1334 of theback surface. The length of the top surface 1331 of the molded cover ismeasured as the distance between the proximal end 1336 and the distalend 1337 of the molded cover 220.

The layer of material 1315 comprises a periphery 1318 and a middleportion 1319. More particularly, the layer of material 1315 comprises aproximal end 1320, a distal end 1321, a first side 1322 and a secondside 1323. The periphery 1318 of the layer of material 1315 comprisesthe proximal end 1320, the distal end 1321, the first side 1322 and thesecond side 1323 of the layer of material 1315. The middle portion 1319of the layer of material 1315 comprises the area between the proximalend 1320, the distal end 1321, the first side 1322 and the second side1323 of the layer of material 1315.

The pocket 1300 formed by the layer of material 1315 further comprises abounded region 1325 and a center 1326. The bounded region 1325 of thepocket 1300 is attached to the back face 1317 of the molded cover 220.The center 1326 of the pocket 1300 is not attached to the back face 1317of the molded cover 220. Stitching 360 in the bounded region 1325 isused to attach the layer of material 1315 to the molded cover 220.

In the embodiment under discussion, the bounded region 1325 of thepocket 1300 comprises a portion of the periphery 1318 of the layer ofmaterial 1315. The bounded region 1325 of the pocket 1300 comprises thedistal end 1321, the first side 1322 and the second side 1323 of thelayer of material 1315. In this embodiment, the bounded region 1325 ofthe pocket 1300 does not comprise the proximal end 1320 of the layer ofmaterial 1315. The center 1326 of the pocket 1300 comprises the middleportion 1319 of the layer of material 1315. The bounded region 1325 iscurved around the center 1326 of the pocket 1300 in a “U” shape. Thebounded region 1325 of the pocket 1300 does not completely enclose thecenter 1326 of the pocket 1300.

In this embodiment, the bounded region 1325 of the pocket comprises acontiguous portion of the periphery 1318 of the layer of material 1315.In an alternate embodiment, the bounded region 1325 of the pocketcomprises a plurality of segmented portions of the periphery 1318 of thelayer of material 1315. In an alternate embodiment the bounded region1325 of the pocket 1300 does not comprise any portion of the periphery1318 of the layer of material 1315. In alternate embodiments, thebounded region 1325 comprises any shape that could be traced on thelayer of material 1315 that partially encloses a center 1326. In oneembodiment, the bounded region 1325 of the pocket 1300 is a portion of acircle's circumference (not shown) that does not touch the periphery1318 of the layer of material 1315. The center 1326 is the area insidethe circle.

In an alternate embodiment, the pocket 1300 comprises a sheet of moldedsilicone. The molded silicone is fused to the molded cover 220 in thebounded region 1325. The opening 1310 of the pocket 1300 comprises thearea between the proximal end 1320 of the layer of material 1315 and thetop surface 1331 of the molded cover 220. The interior 1305 of thepocket 1300 comprises the area between the middle portion 1319 of thelayer of material 1315 and the top surface 1331 of the molded cover 220.

The layer of material 1315 is positioned so that its first side 1322 andsecond side 1323 are positioned over the first side 1333 and second side1334 of the top surface 1331 of the molded cover 220 respectively. Thelayer of material 1315 is positioned so that its distal end 1321 ispositioned over the distal end 1337 of the top surface 1331 of themolded cover 220. The layer of material 1315 is sized so that its lengthis shorter than the length of the top surface 1331 of the molded cover220. In alternate embodiments, the layer of material 1315 is sized sothat its length is equal to, or longer than the length of the topsurface 1331 of the molded cover 220.

The distal end 1321 of the layer of material 1315 is sized so that itswidth is substantially equal to the width of the distal end 1337 of thetop surface 1331 of the molded cover 220. The layer of material 1315 issized so that its width steadily increases toward its proximal end 1320.

The first side 1318 of the proximal end 1320 of the layer of material1315 is fastened to the first side 1333 of the top surface 1331 of themolded cover 220. The second side 1323 of the proximal end 1320 of thelayer of material 1315 is fastened to the second side 1334 of the topsurface 1331 of the molded cover 220. Since the first end 1322 of thelayer of material 1315 is wider than the top surface 1331 of the moldedcover 220, the layer of material 1315 separates from the top surface1331 of the molded cover 220 to form the interior 1305 of the pocket1300.

In an alternate embodiment, the lead electrode assembly 100 lacks amolded cover 220 and the pocket 1300 is attached directly to the backinglayer 130. In another alternate embodiment the lead electrode assembly100 lacks a molded cover 220 and a backing layer 130 and the pocket 1300is attached directly to the electrode 107. In a further alternateembodiment, the pocket 1300 is molded as part of the molded cover 220.

FIG. 41( c) illustrates a cross-sectional side plan view of analternative embodiment of the lead electrode assembly 100. Thisembodiment is substantially similar to the embodiment illustrated inFIGS. 41( a)-41(b). The backing layer 130 of this embodiment, however,further comprises a fin 120 positioned in the interior 1305 of thepocket 1300. The fin 120 of this embodiment is substantially similar tothe fin 120 of the embodiment illustrated in FIG. 22( b).

The fin 120 comprises an integrated fin tab 180 formed on the backinglayer 130. The molded cover 220 covers the integrated fin tab 180 toform the fin 120. The integrated fin tab 180 has a slope-shaped distaledge 183. The sloped-shape of the resulting fin 120 permits the fin 120to fit deeply into the interior 1305 of the pocket 1300. The hood canact to reduce the resistance presented by the tissues of the patientagainst the fin 120 and any tool used to grasp the fin 120 duringinsertion of the lead electrode assembly 100. Such a hood can be placedover any fin discussed in the specification to perform this function orany other function.

In alternate embodiments, appendages other than a fin are positionedbetween the pocket 1300 and the electrode 107, in the interior 1305 ofthe pocket 1300. In one embodiment, a loop such as that discussed withreference to FIGS. 26( a)-26(c) is positioned in the interior 1305 ofthe pocket 1300. In another embodiment, a tube such as that discussedwith reference to FIG. 31 is positioned in the interior 1305 of thepocket 1300.

FIGS. 42( a) and 42(b) illustrate an alternate embodiment of the leadelectrode assembly 100. This embodiment is substantially similar to theembodiment illustrated in FIGS. 41( a)-41(b). FIG. 42( a) illustrates abottom plan view of the lead electrode assembly 100 of this embodiment.In this embodiment, the electrode 107 is thumbnail shaped. FIG. 42( b)illustrates a top plan view of the lead electrode assembly 100 of thisembodiment. The top surface 1331 of the molded cover 220 is shaped toaccommodate the thumbnail shaped electrode 107.

Like the embodiment discussed with reference to FIGS. 41( a) and 41(b),the pocket 1300 comprises a layer of material 1315. In this embodiment,however, the layer of material 1315 has a roughly triangular shape. Thelayer of material 1315 comprises a periphery 1318 and a middle portion1319. More particularly, the layer of material comprises a first side1340, a second side 1341 and a third side 1342 of the layer of material1315. The periphery 1318 of the layer of material comprises the firstside 1340, the second side 1341 and the third side 1342 of the layer ofmaterial 1315. The middle portion 1319 of the layer of material 1315comprises the area between the first side 1340, the second side 1341 andthe third side 1342 of the layer of material 1315.

In this embodiment, the bounded region 1325 of the pocket 1300 comprisesa portion of the periphery 1318 of the layer of material 1315. Thebounded region 1325 of the pocket 1300 comprises the first side 1340 andthe second side 1341 of the layer of material 1315. The center 1326 ofthe pocket 1300 comprises the middle portion 1319 of the layer ofmaterial 1315. The opening 1310 of the pocket 1300 comprises the thirdside 1342 of the layer of material 1315 and the top surface 1331 of themolded cover 220. The bounded region 1325 of the pocket 1300 is curvedaround the center 1326 of the pocket 1300. The bounded region 1325 ofthe pocket 1300 does not completely enclose the center 1326.

In this embodiment, the bounded region 1325 of the pocket comprises acontiguous portion of the periphery 1318 of the layer of material 1315.In an alternate embodiment, the bounded region 1325 of the pocketcomprises a plurality of segmented portions of the periphery 1318 of thelayer of material 1315. In an alternate embodiment the bounded region1325 of the pocket 1300 does not comprise any portion of the periphery1318 of the layer of material 1315.

FIGS. 43( a)-43(c) illustrate a lead electrode assembly manipulationtool 927. The lead electrode assembly manipulation tool 927 illustratedis useful for manipulating a lead electrode assembly 100 having a pocket1300 during the implantation of the lead electrode assembly 100 in apatient. Examples of such a lead electrode assembly 100 embodiments areshown in FIGS. 41( a), 41(b), 42(a) and 42(b).

FIG. 43( a) is a top view of the lead electrode assembly manipulationtool 927 of this embodiment. The lead electrode assembly manipulationtool 927 comprises a handle 1142 (not shown), a rod 1144 and a paddle1350. The rod 1144 and handle 1142 are substantially similar to the rod1144 and handle 1142 of the lead electrode assembly manipulation tool927 illustrated in FIGS. 35( a)-35(d). The handle 1142 is connected tothe rod 1144. The paddle 1350 is attached to the distal end 1148 of therod 1144. The paddle 1350 comprises a disk 1351 and a tang 1161 (phantomview).

FIG. 43( b) is a side view of the lead electrode assembly manipulationtool 927 of this embodiment. The tang 1161 is inserted in the slot 1162in the rod 1144. The tang 1161 is welded into the slot 1162 of the rod1144. The disk 1351 and the tang 1161 are punched from a single sheet ofsteel having a thickness of approximately three mm. In otherembodiments, the disk 1351 and tang 1161 are composed of titanium, apolymeric material or any other material suitable for this purpose. Inone embodiment, the handle 1142, the rod 1144 and the paddle 1350 areall made from the same piece of material.

We now turn to FIG. 43( c) for a description of the use of the leadelectrode assembly manipulation tool 927 in the implantation of a leadelectrode assembly 100 into a patient. As discussed with reference toFIG. 36, an incision 905 is made in the patient 900. As discussed withreference to FIG. 37( a), a subcutaneous path 1090 is created in thepatient 900 with a hemostat 932.

The lead electrode assembly 100 is then captured by the lead electrodeassembly manipulation tool 927. The paddle 1350 of the lead electrodeassembly manipulation tool 927 is inserted into the pocket 1300 of thelead electrode assembly 100. The paddle 1350 is slid into the interior1305 of the pocket via the opening 1310 of the pocket until it can go nofurther. At this point, and with additional reference to FIG. 41( b),the paddle 1350 touches the inner surface 1316 of the distal end 1321 ofthe layer of material 1315.

The lead 21 of the lead electrode assembly 100 can then be pulled towardthe handle 1142 of the lead electrode assembly manipulation tool 927until it is taut. This acts to prevent the paddle 1350 of the leadelectrode assembly manipulation tool 927 from sliding out of the pocket1300 of the lead electrode assembly 100.

The lead electrode assembly manipulation tool 927 may then be used toplace the lead electrode assembly 100 into the incision 905 of thepatient as seen in FIG. 36. The lead electrode assembly manipulationtool 927 may then be used to move the electrode 107 to the terminationpoint 1085 of the subcutaneous path 1090 created as discussed withreference to FIG. 37( c).

The lead electrode assembly 100 is then released from the lead electrodeassembly manipulation tool 927. To achieve this, the lead 21 of the leadelectrode assembly 100 is released so that the paddle 1350 can sliderelative to the pocket 1300 of the lead electrode assembly 100. The leadelectrode assembly manipulation tool 927 may then be extracted from thesubcutaneous path 1090 leaving the lead electrode assembly 100 behind.

Alternately, a curved hemostat, such as the hemostat 930 discussed withreference to FIG. 37( b) could be inserted in the pocket 1300 of thelead electrode assembly 100. The hemostat could then be used to move theelectrode 107 to the termination point 1085 of the subcutaneous path1090 as discussed above. Alternately, a curved hemostat, such as thehemostat 930 discussed with reference to FIG. 37( b) could be used togrip the pocket 1300 of the lead electrode assembly 100, and used tomove the electrode 107 to the termination point 1085 of the subcutaneouspath 1090 as discussed above.

FIGS. 44( a)-44(b) illustrate an alternative embodiment of the leadelectrode assembly 100. The lead electrode assembly 100 of thisembodiment comprises a first channel guide 1401 and a second channelguide 1402. FIG. 44( a) illustrates a cross-sectional rear plan view ofthe lead electrode assembly 100 of this embodiment. The first channelguide 1401 and a second channel guide 1402 each have an interior 1403and an opening 1404. The first channel guide 1401 and the second channelguide 1402 each comprise a strip of material 1406 attached to the moldedcover 220.

The strip of material 1406 comprising the first channel guide 1401 issubstantially rectangular in shape. The strip of material 1406 comprisesa first side 1410 and a second side 1412. The first side 1410 and thesecond side 1412 of the strip of material 1406 are parallel to eachother. In another embodiment, the first side 1410 of the strip ofmaterial 1406 is not parallel to the second side 1412.

The strip of material 1406 further comprises an inner surface 1417 andan outer surface 1416. The strip of material is positioned so that theinner surface 1417 of the first side 1410 faces the outer surface 1330of the molded cover 220. The first side 1410 of the strip of material isattached to the first side 1333 of the top surface 1331 of the moldedcover 220. The second side 1412 of the strip of material 1406 isattached to the skirt 222 of the molded cover 220. The interior 1403 ofthe first channel guide is formed between the inner face 1417 of thestrip of material 1406 and the outer surface 1330 of the molded cover220. The second channel guide is formed in substantially the same way onthe second side 1334 of the molded cover 220.

FIG. 44( b) illustrates a top plan view of the lead electrode assemblyof the embodiment of FIG. 44( a). The strip of material 1406 comprisingthe first channel guide 1401 is substantially rectangular in shapehaving a proximal end 1413 and a distal end 1414. The proximal end 1413and the distal end 1414 of the strip of material 1406 are parallel toeach other. In another embodiment, the proximal end 1413 of the strip ofmaterial 1406 is not parallel to the distal end 1414 of the strip ofmaterial 1406. The opening 1404 of the first channel guide 1401 isformed by the proximal end 1413 of the strip of material 1406 and theouter surface 1330 of the molded cover 220.

The first side 1410 and the second side 1412 (not shown) of the strip ofmaterial 1406 comprising the first channel guide 1401 are positioned sothat they lie parallel to the first side 1333 (phantom view) of themolded cover 220. The second channel guide 1402 is formed and mounted tothe lead electrode assembly 100 in substantially the same way as thefirst channel guide 1401. The first side 1410 and the second side 1412(not shown) of the strip of material 1406 comprising the second channelguide 1402 are positioned so that they lie parallel to the second side1333 (phantom view) of the molded cover 220.

The strips of material 1406 are composed of polyurethane. In analternate embodiment, the strips of material 1406 are composed of anypolymeric material. The strips of material 1406 are fastened to themolded cover 220 with stitching 360. In an alternate embodiment, thestrips of material 1406 are made of molded silicone and attached to themolded cover 220 by fusing them to the molded cover 220. In an alternateembodiment, the first channel guide 1401 and the second channel guide1402 are formed as part of the molded cover 220.

FIG. 45( a)-45(b) illustrates a lead electrode assembly manipulationtool 927. The lead electrode assembly manipulation tool 927 illustratedis useful for manipulating a lead electrode assembly having a firstchannel guide and a second channel guide during the implantation of thelead electrode assembly in a patient. Examples of such a lead electrodeassembly 100 embodiments are shown in FIGS. 44( a)-44(b). FIG. 45( a)illustrates a top plan view of a lead electrode assembly manipulationtool 927. The lead electrode assembly manipulation tool 927 in thisembodiment comprises a handle 1142 (not shown), a rod 1144 and a channelguide fork 1446.

The rod 1144 and handle 1142 are substantially similar to the rod 1144and handle 1142 of the lead electrode assembly manipulation tool 927illustrated in FIGS. 40( a)-40(d). The handle 1142 is connected to therod 1144. The channel guide fork 1446 is attached to the distal end 1148of the rod 1144. The channel guide fork 1446 comprises a pair of tines1451 separated by a gap 1455 and a tine base 1450 having a tang 1161.

The pair of tines 1451 each have a proximal end 1452 and a distal end1453. The proximal ends 1452 of the pair of tines 1451 are attached tothe tine base 1450. The pair of tines 1451 have a substantiallycylindrical form. The distal end 1453 of each of the pair of tines 1451is rounded. The length of the pair of tines 1451 is substantially equalto the length of the first side 1410 of the strips of material 1406comprising the first channel guide 1401 and second channel guide 1402.In alternate embodiments, the length of the tines 1451 is substantiallygreater than or less than the length of the first side 1410 of thestrips of material 1406 comprising the first channel guide 1401 andsecond channel guide 1402.

The tines are separated by a gap 1455 between the proximal ends 1452 ofthe pair of tines 1451. The pair of tines 1451 are substantiallystraight and substantially parallel to each other. The tine base 1450connects the pair of tines 1451 to the distal end 1148 of the rod 1144.The tine base 1450 comprises a tang 1161 (phantom view). The tang 1161is inserted in a slot 1162 in the rod 1144. The tang 1161 is welded inthe slot 1162 of the rod 1144.

The pair of tines 1451 comprising the channel guide fork 1446 arecomposed of steel and have a diameter of approximately three mm. Thetine base 1450 comprising the channel guide fork 1446 is punched from asingle strip of steel having a thickness of approximately three mm. Thepair of tines 1451 are welded to the tine base 1450. In otherembodiments, the channel guide fork 1446 is composed of metal, apolymeric material, or any other material suitable for this purpose. Inone embodiment, the handle 1142, the rod 1144 and the channel guide fork1446 are all made from the same piece of material.

We now turn to FIG. 45( b) for a description of the use of the leadelectrode assembly manipulation tool 927 in the implantation of a leadelectrode assembly 100 into a patient. As discussed with reference toFIG. 36, an incision 905 is made in the patient 900. As discussed withreference to FIG. 37( a), a subcutaneous path 1090 is created in thepatent 900 with a hemostat 932. The lead electrode assembly 100 is thencaptured by the lead electrode assembly manipulation tool 927. The pairof tines 1451 of the lead electrode assembly manipulation tool 927 isinserted into the openings 1404 in the first channel guide 1401 andsecond channel guide 1402.

The electrode 107 is placed into the gap 1455 between the tines of thechannel guide fork 1446. The tines 1451 fit into the interior 1403 ofthe first channel guide 1401 and second channel guide 1402. The moldedcover is slid toward the proximal end 1452 of the tines until it can gono further. The lead 21 of the lead electrode assembly 100 can then bepulled in toward the handle 1142 of the lead electrode assemblymanipulation tool 927 until it is taut. This acts to prevent the leadelectrode assembly 100 from sliding toward the distal end 1453 of thepair of tines 1451 of the channel guide fork 1446.

The lead electrode assembly manipulation tool 927 may then be used toplace the lead electrode assembly 100 into the incision 905 of thepatient as seen in FIG. 36. The lead electrode assembly manipulationtool 927 may then be used to move the electrode 107 through thetermination point 1085 of the subcutaneous path 1090 created asdiscussed with reference to FIG. 37( c).

The lead electrode assembly 100 is then released from the lead electrodeassembly manipulation tool 927. To achieve this, the lead 21 of the leadelectrode assembly 100 is released so that the pair of tines 1451 of thechannel guide fork 1446 of the lead electrode assembly manipulation tool927 can slide relative to the first channel guide 1401 and secondchannel guide 1402 of the lead electrode assembly 100. The leadelectrode assembly manipulation tool 927 may then be extracted from thesubcutaneous path 1090 leaving the lead electrode assembly 100 behind.

FIG. 46( a) illustrates a subcutaneous implantablecardioverter-defibrillator kit 1201 of the present invention. The kitcomprises a group of items that may be used in implanting an S-ICDsystem in a patient. The kit 1201 comprises a group of one or more ofthe following items: an S-ICD canister 11, a lead electrode assembly100, a hemostat 1205, a lead electrode assembly manipulation tool 927, amedical adhesive 1210, an anesthetic 1215, a tube of mineral oil 1220and a tray 1200 for storing these items. In one embodiment, the S-ICDcanister 11 is the S-ICD canister 11 seen in, and discussed withreference to FIG. 1.

The lead electrode assembly 100 is the lead electrode assembly 100 witha rail 1100, and discussed with reference to FIGS. 38( b) and 38(c). Inalternate embodiments, the lead electrode assembly 100 is any leadelectrode assembly 100 including an electrode 107 with an appendage 118;a pocket; or a first and second channel guide for positioning theelectrode 107 during implantation.

The hemostat 1205 is a curved hemostat made of steel having a first end1240 and a second end 1241. The hemostat 1205 has a length, measuredbetween the first end 1240 and the second end 1241 as shown in FIG. 46(b) by dimension L_(Hemostat). The length of the hemostat 1205,L_(Hemostat), is approximately seventy-five cm. In an alternateembodiment, the hemostat 1205 is a length other than seventy-five cm. Inan alternate embodiment, the hemostat 1205 is the enhanced hemostat seenin, and discussed with reference to FIG. 36.

The lead electrode assembly manipulation tool 927 is the lead electrodeassembly manipulation tool 927 with a rail fork 1146. In alternateembodiments, the lead electrode assembly manipulation tool 927 is anylead electrode assembly manipulation tool 927 including a paddle or achannel guide fork. The medical adhesive 1210 comprises a roll of clear,one-inch wide medical adhesive tape. As will be recognized, the medicaladhesive could be a liquid adhesive, or any other adhesive substance.The anesthetic 1215 is a one-ounce tube of lidocaine gel. This can beused as a local anesthetic for the introduction of the lead electrodeassembly 100 as discussed below. As will be recognized, the anestheticcould be any substance that has a pain-killing effect. Alternatively,one could use an injectable form of anesthetic inserted along the pathof the lead. The tube of mineral oil 1220 is a one-ounce tube of mineraloil. This can be used for oiling parts of the electrode connector block17 seen in FIG. 1.

The tray 1200 is a box sized to fit the items of the kit 1201. The tray1200 is composed of molded plastic. In another embodiment, the tray 1200is a cardboard box. One skilled in the art will recognize that the tray1200 may comprise any container capable of containing the items of thekit. In one embodiment, the tray is formed with recessed partitions 1230that generally follow the outline of the items of the kit 1201 to bestored in the tray. In one embodiment, the tray 1200 has packagingmaterial 1225 disposed over it, wherein the packing material 1225provides a sanitary cover for the items of the kit 1201. The packagingmaterial 1225 further acts to contain the items of the kit 1201.

In an alternate embodiment the kit 1201 comprises ten lead electrodeassemblies 100 each comprising a lead 21 having a lead length, l_(Lead),different from the others. In one embodiment, the lead lengths rangebetween approximately five cm and approximately fifty-two cm withapproximately a ten cm difference between the lead length of each leadelectrode assembly 100. In an alternative embodiment, the kit 1201comprises an S-ICD canister 11, a hemostat 1205 and an assortment oflead electrode assemblies 100 each comprising a lead 21 having a leadlength, l_(Lead), different from the others. In one embodiment, the kit1200 further comprises a tray 1201 and an assortment of lead electrodeassemblies 100, each with an electrode 107 curved at a radius rdifferent from the others.

In another embodiment, the kit 1200 includes components sized forsurgery on a patient of a particular size. A kit 1200 for a ten-year-oldchild, for example, includes an S-ICD canister 11 with a length ofapproximately ten cm, a lead electrode assembly 100 with a lead length,L_(Lead) of approximately twelve cm and a radius r of approximately tencm and hemostat 1205 with a hemostat length, L_(Hemostat), ofapproximately twelve cm.

The S-ICD device and method of the present invention may be embodied inother specific forms without departing from the teachings or essentialcharacteristics of the invention. The described embodiments aretherefore to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing description and all changes whichcome within the meaning and range of equivalency of the claims aretherefore to be embraced therein.

1. An implantable lead electrode assembly, the assembly comprising: anelectrode having a tissue contacting surface; a riser coupled to theelectrode and extending in a direction opposed to the tissue contactingsurface; a head coupled to the riser; and a lead coupled to theelectrode, wherein the lead is coupled to the electrode without couplingthrough the riser or head.
 2. The implantable lead electrode assembly ofclaim 1, wherein the riser is substantially planar.
 3. The implantablelead electrode assembly of claim 1, wherein the head is substantiallyplanar.
 4. The implantable lead electrode assembly of claim 1, whereinthe lead is coupled to the electrode closer to the distal end of theelectrode than the proximal end of the electrode.
 5. The implantablelead electrode assembly of claim 1, further comprising a metallicfoundation.
 6. The implantable lead electrode assembly of claim 1,wherein: the riser is substantially planar; and the head issubstantially planar.
 7. An implantable lead electrode assembly, theassembly comprising: an electrode; a riser coupled to the electrode; anda head coupled to the riser; wherein the riser comprises a proximal end,a distal end, a top, and a bottom, and wherein the proximal end iscloser to the distal end at the top of the riser than at the bottom ofthe riser.
 8. The implantable lead electrode assembly of claim 7,further comprising a lead coupled to the electrode, wherein the lead iscoupled to the electrode without coupling through the riser or head. 9.An implantable lead electrode assembly, the assembly comprising: anelectrode; a riser coupled to the electrode; a head coupled to theriser; a backing layer; and a foundation having a front side and a backside, wherein the backing layer is disposed between the front side ofthe foundation and the electrode, and the riser is secured to the backside of the foundation.
 10. The implantable lead electrode assembly ofclaim 9, wherein the backing layer and/or foundation electricallyinsulate a side of the electrode.
 11. An implantable lead electrodeassembly, the assembly comprising: an electrode; a riser coupled to theelectrode; a head coupled to the riser; and a cover assembly including askirt partially covering a front side of the electrode, and a backportion, wherein the back portion and the riser generally electricallyisolate a back side of the electrode.
 12. The implantable lead electrodeassembly of claim 11, further comprising a lead coupled to theelectrode, wherein the lead is coupled to the electrode without couplingthrough the riser or head.
 13. The implantable lead electrode assemblyof claim 12, further comprising: a backing layer; and a foundationhaving a front side and a back side, wherein the backing layer isdisposed between the front side of the foundation and the electrode, andthe riser is secured to the back side of the foundation.
 14. Animplantable cardioverter-defibrillator comprising: a housing; and a leadelectrode assembly coupled to the housing, the lead electrode assemblyincluding an electrode having a tissue contacting surface, a risercoupled to the electrode and extending in a direction opposed to thetissue contacting surface, and a head coupled to the riser.
 15. Theimplantable cardioverter-defibrillator of claim 14, wherein the riser issubstantially planar.
 16. The implantable cardioverter-defibrillator ofclaim 14, wherein the head is substantially planar.
 17. The implantablecardioverter-defibrillator of claim 14, wherein the riser comprises aproximal end, a distal end, a top, and a bottom, and wherein theproximal end is closer to the distal end at the top of the riser than atthe bottom of the riser.
 18. The implantable cardioverter-defibrillatorof claim 14, further comprising a lead coupled between the housing andthe electrode, wherein the lead is coupled to the electrode withoutcoupling through the riser or head.
 19. The implantablecardioverter-defibrillator of claim 14, further comprising a leadcoupled between the housing and the electrode, the lead being coupled tothe electrode closer to the distal end of the electrode than theproximal end of the electrode.
 20. The implantablecardioverter-defibrillator of claim 14, wherein the lead electrodeassembly further includes: a backing layer; and a foundation having afront side and a back side, wherein the backing layer is disposedbetween the front side of the foundation and the electrode, and theriser is secured to the back side of the foundation.
 21. The implantablecardioverter-defibrillator of claim 14, wherein: the riser issubstantially planar; the head is substantially planar.
 22. Theimplantable cardioverter-defibrillator of claim 14, wherein the lead iscoupled to the electrode without coupling through the riser or head. 23.The implantable cardioverter-defibrillator of claim 22, wherein the leadelectrode assembly further includes: a backing layer; and a foundationhaving a front side and a back side, wherein the backing layer isdisposed between the front side of the foundation and the electrode, andthe riser is secured to the back side of the foundation.